Horrible gas mileage

[JPJPJP]

Hi guys, I'm not sure if this is the right thread cuz I'm fairly new to this. Anyways, I got my 2010 GS sedan about a month ago, and I'm getting horrible gas mileage on it. I filled up sometime last week, and I went exactly 404 Kms when the gas was down to 1 bar with the gas light on. I never push my car, accelerate at moderate pace, and only cruise at speed limit or 5-10 Kms over, if anything. I give adequate time for the car to warm up. There was an aftermarket exhaust on the car. It runs on 18 inch rims on 225/40r18 tires, only about a .08% difference from stock. It is about 65% city driven, 35% highway. Even with it being mostly city Kms, I don't think that is normal gas usage.. Can anyone else tell me otherwise? Any other possible problems? Please let me know. Any help is appreciated!

Thank you,
JP

[pwdunmore]

That seems very low... 404km for a tank is as where the MS3 are. I don't have a good idea of what it would be that could be causing the bad gas mileage... I would check all the normal sources like spark plugs for carbon build up and air filter for dirt. Hope you find out what is making it gulp gas cuz you should be driving a speed3 with that gas mileage lol.

[trulankan]

how many KMs are on it? have you kept up with the maintenance schedule? Try using a fuel injector cleaner and see if theres an improvement. These cars arent very good for mostly city driving in terms of gas. the best mileage i've gotten on my 08 2.3L so far is 580km/tank with mostly highway.

[Booter22]

what 18" rims do you have? that could make a slight difference too if they are stupid heavy. use fuelly to track your mileage however, your looking at it based on down to the 1 bar left. well if for some reason there was 15L+ of fuel in the tank then thats not terriable. not to mention it might not be an average fuel economy but it depends as well where you drive. do you do alot of stop and go. up hill, is your car full of stuff, passengers so on. remember when every vehicles fuel economy is calculated its with a brand new car. on a flat surface in perfect temperatures running the same speed all the time. but as others have said how is your cars up keep? regular services. air filters, try synth oil, fuel / injection service. so on..

but track the next few tanks on fuelly to see what the cars avg is. my cars at 8.0L / 100 KM and my gfs is 7.7L/100KM

[mazdaagain]

I went exactly 404 Kms when the gas was down to 1 bar with the gas light on.

It's 404 km with 1 bar left so the tank isn't empty yet. The last bar should be good for another 40-50 km.

Never judge gas mileage from only 1 tank. I've had a tank at about 450 km before and the next tank at well over 600 km. Use the Fuelly website and track your gas mileage over an extended period of time and see what that tells you. Also check your tire inflation. If its off significantly it can impact your gas mileage.

[Odin]

That seems very low... 404km for a tank is as where the MS3 are. I don't have a good idea of what it would be that could be causing the bad gas mileage... I would check all the normal sources like spark plugs for carbon build up and air filter for dirt. Hope you find out what is making it gulp gas cuz you should be driving a speed3 with that gas mileage lol.

That is pretty bad considering I get ~360km for 100% city driving on MS3. ECU problem maybe?

[JPJPJP]

That is pretty bad considering I get ~360km for 100% city driving on MS3. ECU problem maybe?
What is an ECU? Sorry for being so noobish..

[The Wolf]

You're not accurately measuring your fuel usage. After you went 404 km, did you full the car up? How much gas did you put in it? The gauge could be giving you a bad reading. Who knows, maybe the needle on your fuel gauge was positioned improperly during assembly.

For starters, try to accurately track your fuel use :)

[JPJPJP]

what 18" rims do you have? that could make a slight difference too if they are stupid heavy. use fuelly to track your mileage however, your looking at it based on down to the 1 bar left. well if for some reason there was 15L+ of fuel in the tank then thats not terriable. not to mention it might not be an average fuel economy but it depends as well where you drive. do you do alot of stop and go. up hill, is your car full of stuff, passengers so on. remember when every vehicles fuel economy is calculated its with a brand new car. on a flat surface in perfect temperatures running the same speed all the time. but as others have said how is your cars up keep? regular services. air filters, try synth oil, fuel / injection service. so on..

but track the next few tanks on fuelly to see what the cars avg is. my cars at 8.0L / 100 KM and my gfs is 7.7L/100KM

They are Touren TR9 18inch alloy rims. I have started on fuelly and track my exact usage, but since I got it 1.5 months ago. It probably averages around 425-450/tank. My mom has a 2010 GT, and gets 600-700 Kms, and that's with her bigger 2.5 engine

[DDUKI]

Try to keep track the L/100km, not km/tank, as that is really not accurate...at all..
fuelly should give it out if you started using it...

[JPJPJP]

You're not accurately measuring your fuel usage. After you went 404 km, did you full the car up? How much gas did you put in it? The gauge could be giving you a bad reading. Who knows, maybe the needle on your fuel gauge was positioned improperly during assembly.

For starters, try to accurately track your fuel use :)

I am going to fill up in a bit, and I'll accurately track it using fuelly, and post my results here

[JPJPJP]

how many KMs are on it? have you kept up with the maintenance schedule? Try using a fuel injector cleaner and see if theres an improvement. These cars arent very good for mostly city driving in terms of gas. the best mileage i've gotten on my 08 2.3L so far is 580km/tank with mostly highway.

I'll try the fuel injector cleaner. It has 83xxx Kms on it, can't remember exactly. I had an 2.3 06 GT before this and was getting around 6-700 km/tank. That's why I think there is something wrong with the car. As for maintenance schedule. I'm not 100% sure, as there are no paper records. But the dealer said the car was properly maintained. The oil was changed when I got the car

[JPJPJP]

Try to keep track the L/100km, not km/tank, as that is really not accurate...at all..
fuelly should give it out if you started using it...

I am starting a fuelly today

[Booter22]

That is pretty bad considering I get ~360km for 100% city driving on MS3. ECU problem maybe?

if it was ecu im sure an eng light would come on for something. i mean could maybe benifit from a software update if there is any.

and in another thread -
I got my 06 Mazda 3 GT 89XXX KMs for $8700 including all taxes, fees and everything! I got it at a used car dealership in July! You can bargain the price down a bit more than 9000, especially if that doesn't include tax! just be patient, and the right car will come :chuckle

so you have an older 2.3L GT which is already prone to pretty bad fuel economy as it is. cant really compare from your 2.3L to your moms 2010 GT.

[DumpInfo]

Not to burst your bubble but when I had my 3 (2.3L) the best I got was 400kms to a tank. Was also on top of my maintenance. Not sure if your gonna get any better.

[sarujo]

This is an used car with mods - 18" and an aftermarket exhaust with mileage at 83000 according to the OP. As other have stated before, fuelly tracking is required.

Since maintenance records are not available, I would immediately check/change the air filter, put in a few tank fulls of fuel injector cleaner (ie Redline SI-1 etc), check tire pressures all around. At this mileage, cleaning the throttle body is likely in order as well. Make sure your alignment is good and I'm willing to bet the original brakes are on the car. It wouldn't hurt to jack up the front end of the car and then rear to check that all wheels spin freely without resistance from seized or partially seized pads.

And let's not forget what that after market exhaust may be doing. Take your finger and wipe the inside of the exhaust tip. If you get lots of black residue, your motor is likely running rich. The exhaust tip on my 2010 2.0L with 51000km's is nice and clean - no black!

Good luck and keep us posted! :)

[silverstarmazda]

try doing a tune up. change the spark plugs, filter, and check for alignment. bigger wheels can cause more resistance too. tire inflation is also a huge part so check that too. change the oil and filters too if your getting to that point. and also try to seafoam the engine. fuel injector cleaner mentioned above by trulankan can make a difference also. thats all i can think of now. i get about 410-430km on a full tank (04 hatch 4spd) maybe more if im not stuck in toronto traffic

[silverstarmazda]

This is an used car with mods - 18" and an aftermarket exhaust with mileage at 83000 according to the OP. As other have stated before, fuelly tracking is required.

Since maintenance records are not available, I would immediately check/change the air filter, put in a few tank fulls of fuel injector cleaner (ie Redline SI-1 etc), check tire pressures all around. At this mileage, cleaning the throttle body is likely in order as well. Make sure your alignment is good and I'm willing to bet the original brakes are on the car. It wouldn't hurt to jack up the front end of the car and then rear to check that all wheels spin freely without resistance from seized or partially seized pads.

And let's not forget what that after market exhaust may be doing. Take your finger and wipe the inside of the exhaust tip. If you get lots of black residue, your motor is likely running rich. The exhaust tip on my 2010 2.0L with 51000km's is nice and clean - no black!

Good luck and keep us posted! :)

lol damn, posted at same time

[lawlzen]

This is an used car with mods - 18" and an aftermarket exhaust with mileage at 83000 according to the OP. As other have stated before, fuelly tracking is required.

Since maintenance records are not available, I would immediately check/change the air filter, put in a few tank fulls of fuel injector cleaner (ie Redline SI-1 etc), check tire pressures all around.

Props for Redline SI-1. If you're in the west-end JRP stock it for about 11$.

[brucewayne]

Props for Redline SI-1. If you're in the west-end JRP stock it for about 11$.

can tire is selling gumout regane for $6-7(usually double) for the next couple of days. however, it having PEA in it is uncertain although likely.

[silverstarmazda]

the stuff like stp and gumout is usually recommended to be use with a full tank of gas for the whole bottle.....




i use to dump the whole bottle in with only 1/4 of a tank LOL. more concentrated, then put another 1/4 a day later.

[r4BBiT]

They are Touren TR9 18inch alloy rims. I have started on fuelly and track my exact usage, but since I got it 1.5 months ago. It probably averages around 425-450/tank. My mom has a 2010 GT, and gets 600-700 Kms, and that's with her bigger 2.5 engine

From what I can see those rims 18x8 weigh 28.7lbs, which is almost double the stock GS 16" rims which are at 16lbs IIRC.

Take a look at this: http://ecomodder.com/forum/showthread.php/rotational-weight-20136.html

That's why you don't buy "performance" rims at Canadian Tire: http://tires.canadiantire.ca/en/wheels/alloy-wheels/product/1418593P/touren-tr9-3190-in-matte-black/1418608/

[silverstarmazda]

From what I can see those rims 18x8 weigh 28.7lbs, which is almost double the stock GS 16" rims which are at 16lbs IIRC.

Take a look at this: http://ecomodder.com/forum/showthread.php/rotational-weight-20136.html

That's why you don't buy "performance" rims at Canadian Tire: http://tires.canadiantire.ca/en/wheels/alloy-wheels/product/1418593P/touren-tr9-3190-in-matte-black/1418608/

+1, i know my after market rims are heavier than my oem.

[Booter22]

the stuff like stp and gumout is usually recommended to be use with a full tank of gas for the whole bottle.....
i use to dump the whole bottle in with only 1/4 of a tank LOL. more concentrated, then put another 1/4 a day later.

pretty sure they advise to put it in with a whole tank is the high concentration can damage fuel components if not diluted.. but its advised to put in and then fill up to allow it to mix otherwise it can sit on the top of the fuel and not allow proper mixture.

[silverstarmazda]

pretty sure they advise to put it in with a whole tank is the high concentration can damage fuel components if not diluted.. but its advised to put in and then fill up to allow it to mix otherwise it can sit on the top of the fuel and not allow proper mixture.

im not a big believer of the "more concentrated" label. its not very strong to begin with either and the ingredients in it are already present in the fuel. theres also another fuel injector system cleaner that actually sends this kind of cleaner through the fuel rail %100 without fuel. you actually disconnect the fuel line, remove fuel pump fuse, and connect the tool to the fuel rail that feeds pure cleaner. air pressurizes the tool and the cleaner acts as the fuel. start the engine and your car is running on %100 fuel injector cleaner.

yea, i mis it like that too after i put it in. but when im not putting any gas in. i find an empty lot and "mix" it lol

[kilo4321]

This is an used car with mods - 18" and an aftermarket exhaust with mileage at 83000 according to the OP. As other have stated before, fuelly tracking is required.

Since maintenance records are not available, I would immediately check/change the air filter, put in a few tank fulls of fuel injector cleaner (ie Redline SI-1 etc), check tire pressures all around. At this mileage, cleaning the throttle body is likely in order as well. Make sure your alignment is good and I'm willing to bet the original brakes are on the car. It wouldn't hurt to jack up the front end of the car and then rear to check that all wheels spin freely without resistance from seized or partially seized pads.

And let's not forget what that after market exhaust may be doing. Take your finger and wipe the inside of the exhaust tip. If you get lots of black residue, your motor is likely running rich. The exhaust tip on my 2010 2.0L with 51000km's is nice and clean - no black!

Good luck and keep us posted! :)

Regarding mods, when I first got my car with 4600km (2011 GX) I was getting roughly 650km a tank, added CS SRI... Saw around 550-600 a tank. Added CS CBE and race pipe which makes the car run rich as balls, now I'm lucky if I get 450km a tank 50/50 driving (at 16,xxxKm now). But my heavy a$$ EKM3 rims with larger OD than stock (215/45/18) sure don't help at all, but makes my 1.75" drop look amazing. -because racecar-
Synopsis: want a fuel efficient ride? De-mod and part out! Lol

[asyed]

Not to burst your bubble but when I had my 3 (2.3L) the best I got was 400kms to a tank. Was also on top of my maintenance. Not sure if your gonna get any better.

I got my 3 to go about 570 kms in one tank before i filled up since i was on reserve.....

[eaybulut]

Hi guys, I'm not sure if this is the right thread cuz I'm fairly new to this. Anyways, I got my 2010 GS sedan about a month ago, and I'm getting horrible gas mileage on it. I filled up sometime last week, and I went exactly 404 Kms when the gas was down to 1 bar with the gas light on. I never push my car, accelerate at moderate pace, and only cruise at speed limit or 5-10 Kms over, if anything. I give adequate time for the car to warm up. There was an aftermarket exhaust on the car. It runs on 18 inch rims on 225/40r18 tires, only about a .08% difference from stock. It is about 65% city driven, 35% highway. Even with it being mostly city Kms, I don't think that is normal gas usage.. Can anyone else tell me otherwise? Any other possible problems? Please let me know. Any help is appreciated!

Thank you,
JP

Hey chief!

That is quite low, considering I'm getting better mileage (km) on my 04 - 3 - sedan - 2.3L However.. at one point, I was running into similar concerns, just like you are. I have tried replacing the spark plugs.. which resulted in no efficiency whatsoever. As a fellow TM3 member stated, try fuel injector cleaners... I tried STP and the Lucas Oil one as well. Which, I am inclined to have helped a little, because I noticed an improvement, and since its been a while since I last used it, I'm starting to realize low mileage again. In addition, I definitely recommend the usual maintenance, especially oil changes. I notice how much smoother the car feels after an oil change, compared to how it feels bogged down, if I haven't had one in a while (past the 4500 / 5000km mark). Also, I suggest you basing your results on at least 2 tanks worth of gas, running to the last drop on your last tank full (make sure you have some spare fuel to put in when you run out / stall and also ensure you are somewhat close to a gas station). Check your total km driven, divide it by total of how much fuel you put in the first time + 55L since you are running to the last drop the 2nd time around (assuming you have a 55L tank). Despite all of the above, what I feel most influenced my mileage is the way I drove the car. When I was in "testing the mileage" mode, I didnt let it warm up too long.. approx 1 to 2 minutes MAX.. didn't want it sitting there wasting gas and subsequently affecting my results. I didn't accelerate as fast as I usually do and also tried to maintain a 50-50 ratio between city to highway (again, not speeding on the highway either, just following the speed limit). How do you maintain a 50-50 ratio? if you feel you have driven too much city lately, take a drive on the highway for 15-30 minutes.. sounds stupid.. but I had to balance it somehow. I got frustrated with no one being able to figure out what the hell was up with my mileage. In addition, I also tried to not use the AC or heat -- it was summer when I was testing btw. My overall results were basically 475km / avg on 2 tanks worth of gas, with what I would have called a 50-50 balance driving, and having used the fuel injector cleaners; as opposed to my barely 400km driving my usual way (65 city, 35 highway, accelerating as I wish, letting the car warm up in excess of 2 minutes, etc). The most I have ever got on a full tank (again, to the LAST drop, until I stalled) was 505km on the dot. As a final note.. I have realized that my car prefers Regular gasoline, as opposed to the "premium" . I have tried to use premium many times on my car, but performance wise, no difference. Since it burns a little better, it did get me lower mileage as opposed to the regular. Always remember to not use premium gasoline and fuel injector cleaners, from what I understand potential issues can result. Hope it was somewhat helpful,

Cheers.

[loosecannon]

I'm having similar problems with horrible mileage.

I have a CAI, Vibrant Headers and CS CBE and I averaged 550-580 before the gas lights comes on. (I do about 80% highway. I also have a lead foot)

A little over a month ago, my mileage started to drop and there seemed to be a loss of power. Eventually, a CEL came on and I was going to get an oil change so I got the mechanic to check it. Turns out, (according to him) my oxygen sensor died. He cleared it, but I'm waiting for it to come back so I can get a second opinion. It's been about a week and it hasn't come back and my mileage is suffering even more. I lose my first dot at 35km. My gas light comes on at 430km if I'm lucky to get that high.

I've looked into Seafoam to see if that'll help, but I'm getting mixed reviews about it all over the interwebs. Whoever has tried it can chime in about it?

I don't know what to do...

[thenightvision88]

I have an 08 3 with the 2.3L and the best I've gotten so far is 460 and that was roughly 50 - 50 driving with a heavy foot... but I usually average about 400 - 430 kms

[kilo4321]

I'm having similar problems with horrible mileage.

I have a CAI, Vibrant Headers and CS CBE and I averaged 550-580 before the gas lights comes on. (I do about 80% highway. I also have a lead foot)

A little over a month ago, my mileage started to drop and there seemed to be a loss of power. Eventually, a CEL came on and I was going to get an oil change so I got the mechanic to check it. Turns out, (according to him) my oxygen sensor died. He cleared it, but I'm waiting for it to come back so I can get a second opinion. It's been about a week and it hasn't come back and my mileage is suffering even more. I lose my first dot at 35km. My gas light comes on at 430km if I'm lucky to get that high.

I've looked into Seafoam to see if that'll help, but I'm getting mixed reviews about it all over the interwebs. Whoever has tried it can chime in about it?

I don't know what to do...

Love seafoam. I put that sh*t in everything lol

[aris]

I'm having similar problems with horrible mileage.

I have a CAI, Vibrant Headers and CS CBE and I averaged 550-580 before the gas lights comes on. (I do about 80% highway. I also have a lead foot)

A little over a month ago, my mileage started to drop and there seemed to be a loss of power. Eventually, a CEL came on and I was going to get an oil change so I got the mechanic to check it. Turns out, (according to him) my oxygen sensor died. He cleared it, but I'm waiting for it to come back so I can get a second opinion. It's been about a week and it hasn't come back and my mileage is suffering even more. I lose my first dot at 35km. My gas light comes on at 430km if I'm lucky to get that high.

I've looked into Seafoam to see if that'll help, but I'm getting mixed reviews about it all over the interwebs. Whoever has tried it can chime in about it?

I don't know what to do...

the oxygen sensor will cause you to burn a lot of gas... If your mechanic checked the code and said it was your oxygen sensor then why wouldn't you believe him? Maybe you need a new mechanic if you don't trust him?

[eaybulut]

the oxygen sensor will cause you to burn a lit gas... If your mechanic checked the code and said it was your oxygen sensor then why wouldn't you believe him? Maybe you need a new mechanic if you don't trust him?

+1 re: trusting your mechanic.. I bet he's having trust issues based on what his mechanic quoted him.

A burnt out / dead o2 sensor apparently does quite a bit to your mileage. However, there are many other things which you should / can test first.

[JPJPJP]

From what I can see those rims 18x8 weigh 28.7lbs, which is almost double the stock GS 16" rims which are at 16lbs IIRC.

Take a look at this: http://ecomodder.com/forum/showthread.php/rotational-weight-20136.html

That's why you don't buy "performance" rims at Canadian Tire: http://tires.canadiantire.ca/en/wheels/alloy-wheels/product/1418593P/touren-tr9-3190-in-matte-black/1418608/

I didn't realize the rims were that heavy. They came with it when I bought the car. I'm switching to winters soon, so maybe i'll get a little more gas efficiency. If so, I'll be looking to get rid of the rims and pick up a new, lighter set next year.

[JPJPJP]

pretty sure they advise to put it in with a whole tank is the high concentration can damage fuel components if not diluted.. but its advised to put in and then fill up to allow it to mix otherwise it can sit on the top of the fuel and not allow proper mixture.

I'm gonna stop by Canadian Tire today, and i'll try it out. and I'll see if anything improves and let everyone know.

[JPJPJP]

Hey chief!

That is quite low, considering I'm getting better mileage (km) on my 04 - 3 - sedan - 2.3L However.. at one point, I was running into similar concerns, just like you are. I have tried replacing the spark plugs.. which resulted in no efficiency whatsoever. As a fellow TM3 member stated, try fuel injector cleaners... I tried STP and the Lucas Oil one as well. Which, I am inclined to have helped a little, because I noticed an improvement, and since its been a while since I last used it, I'm starting to realize low mileage again. In addition, I definitely recommend the usual maintenance, especially oil changes. I notice how much smoother the car feels after an oil change, compared to how it feels bogged down, if I haven't had one in a while (past the 4500 / 5000km mark). Also, I suggest you basing your results on at least 2 tanks worth of gas, running to the last drop on your last tank full (make sure you have some spare fuel to put in when you run out / stall and also ensure you are somewhat close to a gas station). Check your total km driven, divide it by total of how much fuel you put in the first time + 55L since you are running to the last drop the 2nd time around (assuming you have a 55L tank). Despite all of the above, what I feel most influenced my mileage is the way I drove the car. When I was in "testing the mileage" mode, I didnt let it warm up too long.. approx 1 to 2 minutes MAX.. didn't want it sitting there wasting gas and subsequently affecting my results. I didn't accelerate as fast as I usually do and also tried to maintain a 50-50 ratio between city to highway (again, not speeding on the highway either, just following the speed limit). How do you maintain a 50-50 ratio? if you feel you have driven too much city lately, take a drive on the highway for 15-30 minutes.. sounds stupid.. but I had to balance it somehow. I got frustrated with no one being able to figure out what the hell was up with my mileage. In addition, I also tried to not use the AC or heat -- it was summer when I was testing btw. My overall results were basically 475km / avg on 2 tanks worth of gas, with what I would have called a 50-50 balance driving, and having used the fuel injector cleaners; as opposed to my barely 400km driving my usual way (65 city, 35 highway, accelerating as I wish, letting the car warm up in excess of 2 minutes, etc). The most I have ever got on a full tank (again, to the LAST drop, until I stalled) was 505km on the dot. As a final note.. I have realized that my car prefers Regular gasoline, as opposed to the "premium" . I have tried to use premium many times on my car, but performance wise, no difference. Since it burns a little better, it did get me lower mileage as opposed to the regular. Always remember to not use premium gasoline and fuel injector cleaners, from what I understand potential issues can result. Hope it was somewhat helpful,

Cheers.

Thanks.. It's good to know that someone else has been in the same situation and can help me out. I'm doing some testing, and tracking my mileage on fuelly. So i'll post results in about 2-3 weeks, when i've gone through 2-3 tanks of gas. But i'm gonna try all of your recommendations.

[JPJPJP]

I'm fairly new to the forum, but I am amazed as to how helpful everyone is being. Great Forum and Great Community :thumbsup

[loosecannon]

the oxygen sensor will cause you to burn a lot of gas... If your mechanic checked the code and said it was your oxygen sensor then why wouldn't you believe him? Maybe you need a new mechanic if you don't trust him?


+1 re: trusting your mechanic.. I bet he's having trust issues based on what his mechanic quoted him.

A burnt out / dead o2 sensor apparently does quite a bit to your mileage. However, there are many other things which you should / can test first.

It was actually the first time I visited this mechanic cause they deal with lowered cars. It just so happened that I got a CEL at the same time. And yes, it was what he quoted me that's making me feel the way I feel.

[eaybulut]

It was actually the first time I visited this mechanic cause they deal with lowered cars. It just so happened that I got a CEL at the same time. And yes, it was what he quoted me that's making me feel the way I feel.

I'd definitely wait for the CEL to come up again. Sounds like an iffy situation. You don't even need to go to a mechanic to figure out what the light is for. This is going to sound stupid.. but invest in a decent ODBII reader. Saves you time and money to know what the issue is without taking it to the mechanic. Once you figure out the code, google it. Worst case scenario, if you feel like its not a project you want to take on yourself.. go to a mechanic.

[Dynames]

This sounds very similar with my situation. Except my mz3 is this years model. I've only gotten over 400km a tank all of ONE time. When u said u lose your first block at 35km I was thinking thats totally normal for me lol. I'm getting like 11.5km/100 on fuelly so yeah... I am a spiriter driver but my mileage has always been pretty bad to begin with.


I'm having similar problems with horrible mileage.

I have a CAI, Vibrant Headers and CS CBE and I averaged 550-580 before the gas lights comes on. (I do about 80% highway. I also have a lead foot)

A little over a month ago, my mileage started to drop and there seemed to be a loss of power. Eventually, a CEL came on and I was going to get an oil change so I got the mechanic to check it. Turns out, (according to him) my oxygen sensor died. He cleared it, but I'm waiting for it to come back so I can get a second opinion. It's been about a week and it hasn't come back and my mileage is suffering even more. I lose my first dot at 35km. My gas light comes on at 430km if I'm lucky to get that high.

I've looked into Seafoam to see if that'll help, but I'm getting mixed reviews about it all over the interwebs. Whoever has tried it can chime in about it?

I don't know what to do...

[CanadianReaper]

There are some good comments above re: MAF sensor, tire pressures (these are important for my gas mileage), checking spark plugs (though usually good till 100k?)

The 2.5L on the 2010 GS is rated for 10.2L/100km City. You are sitting around 11.1 assuming 45L (1 bar left) and 404km as per OP. I got much worse than that last winter when (stupidly) letting the car idle for 5-10 min in the driveway before leaving. My best (granny) city driving I've done has been right around 10L/100km. TBH I don't think there's much to be done other to improve your numbers other than driving style. The highway mileage I get is between 8-9L/100km driving 100-120 in stop and go traffic 404-DVP M-F.

[brucewayne]

I'd definitely wait for the CEL to come up again. Sounds like an iffy situation. You don't even need to go to a mechanic to figure out what the light is for. This is going to sound stupid.. but invest in a decent ODBII reader. Saves you time and money to know what the issue is without taking it to the mechanic. Once you figure out the code, google it. Worst case scenario, if you feel like its not a project you want to take on yourself.. go to a mechanic.

is this an overpriced one or a good deal right now??

http://www.canadiantire.ca/AST/browse/4/Auto/AutoTools/AutoCodeReaders/PRDOVR~0251063P/Launch+Technology+OBD+Book.jsp?locale=en

[eaybulut]

This sounds very similar with my situation. Except my mz3 is this years model. I've only gotten over 400km a tank all of ONE time. When u said u lose your first block at 35km I was thinking thats totally normal for me lol. I'm getting like 11.5km/100 on fuelly so yeah... I am a spiriter driver but my mileage has always been pretty bad to begin with.

You must mean 11L / 100km ... right?

[eaybulut]

is this an overpriced one or a good deal right now??

http://www.canadiantire.ca/AST/browse/4/Auto/AutoTools/AutoCodeReaders/PRDOVR~0251063P/Launch+Technology+OBD+Book.jsp?locale=en

I haven't seen or used that one personally, but based on the 1 good review about it, and the fact that 3 out of 4 people DISAGREED with it, sounds like its not as glorious as it appears. The one I have used in the past is this one --http://www.canadiantire.ca/AST/browse/4/Auto/AutoTools/AutoCodeReaders/PRDOVR~0251030P/OBD+II+Code+Reader.jsp?locale=en

But I'm guessing you don't want to shell out $200+tax just to read what the error code it is, which is a fair argument. Your call on this one bud. Just keep an eye out for it, I remember it fell to $149 at one point.

[loosecannon]

This sounds very similar with my situation. Except my mz3 is this years model. I've only gotten over 400km a tank all of ONE time. When u said u lose your first block at 35km I was thinking thats totally normal for me lol. I'm getting like 11.5km/100 on fuelly so yeah... I am a spiriter driver but my mileage has always been pretty bad to begin with.

I used to lose the first bar between 80-100 km. Now I'm crying on the inside...

[Dynames]

I used to lose the first bar between 80-100 km. Now I'm crying on the inside...

My car only has 11,000 on it but its had more than enough time to be broken-in. I have a hard time believing it eats this much gas especially when people driving speed 3's are getting a lot better gas mileage than I am so there must be some underlying problem. Only way I can hit even 400 now is if I go until the last bar is gone o.o

[loosecannon]

My car only has 11,000 on it but its had more than enough time to be broken-in. I have a hard time believing it eats this much gas especially when people driving speed 3's are getting a lot better gas mileage than I am so there must be some underlying problem. Only way I can hit even 400 now is if I go until the last bar is gone o.o

Are you doing 100% city? Our cars are horrible in city driving. Unless you have a lemon...

[Dynames]

Are you doing 100% city? Our cars are horrible in city driving. Unless you have a lemon...

Nope, I go to school 4 days a week @ seneca and I take the 404 on the way back home daily. Even in the summer I've almost never seen anything over 400km on a tank. Last fill up with 1 bar left and the fuel light on I had gone only 360km, filled up for 41L's which would give me 11.5L/100

I've gone to markham mazda where I got my car and they've been useless pretty much.

[eaybulut]

Nope, I go to school 4 days a week @ seneca and I take the 404 on the way back home daily. Even in the summer I've almost never seen anything over 400km on a tank. Last fill up with 1 bar left and the fuel light on I had gone only 360km, filled up for 41L's which would give me 11.5L/100

I've gone to markham mazda where I got my car and they've been useless pretty much.

Something is definitely not right. a) it seems like your reserve is holding a lot more than normal (i.e. you have 14L (aka 25% of the overall gas you put in) worth of gas left when you have 0 bars remaining on dash -- and you're thinking I gotta fill up, but when you do... you only filled up 41 liters. OR b) there is, as you said, an underlying problem. The 3 I use now is an 04, and I'm getting better mileage than you. Have you considered ever going to the last drop, as I have suggested before? Based on my experience with the 3... and again, this sounds stupid, but the car has less power when there is only a small amount of fuel left and I actually feel like I get the most mileage on the last 1/4 of the tank (maybe my gauge is broken?). Fill up your tank to the rim, so you ensure you have 55L, buy an extra 3-5L in a spare fuel tank and just drive the car until you run to the last drop. That should give you a much better idea as to your actual consumption. As a side note-- if your car still has 25% in reserve while you have done 360km on 41km.. your overall consumption should be around 480-500 on an actual full tank worth. Looks better, but in my opinion its still falling short of expectations and not getting enough mpg (km/L).

[r4BBiT]

Nope, I go to school 4 days a week @ seneca and I take the 404 on the way back home daily. Even in the summer I've almost never seen anything over 400km on a tank. Last fill up with 1 bar left and the fuel light on I had gone only 360km, filled up for 41L's which would give me 11.5L/100

I've gone to markham mazda where I got my car and they've been useless pretty much.

That's definitely not normal! My 2.0 on the highway driving around 130-140 still gets around 8L/100km. Before I had CS SRI I was getting between 6.5 - 7, but then I probably just driver harder now to hear it, lol.

[r4BBiT]

Something is definitely not right. a) it seems like your reserve is holding a lot more than normal (i.e. you have 14L (aka 25% of the overall gas you put in) worth of gas left when you have 0 bars remaining on dash -- and you're thinking I gotta fill up, but when you do... you only filled up 41 liters. OR b) there is, as you said, an underlying problem. The 3 I use now is an 04, and I'm getting better mileage than you. Have you considered ever going to the last drop, as I have suggested before? Based on my experience with the 3... and again, this sounds stupid, but the car has less power when there is only a small amount of fuel left and I actually feel like I get the most mileage on the last 1/4 of the tank (maybe my gauge is broken?). Fill up your tank to the rim, so you ensure you have 55L, buy an extra 3-5L in a spare fuel tank and just drive the car until you run to the last drop. That should give you a much better idea as to your actual consumption. As a side note-- if your car still has 25% in reserve while you have done 360km on 41km.. your overall consumption should be around 480-500 on an actual full tank worth. Looks better, but in my opinion its still falling short of expectations and not getting enough mpg (km/L).

Running the tank dry is not good for your fuel pump so I don't know why you keeping suggesting that. It simply does not matter that he didn't use all of the fuel if you fill up full both time and reset your trip odometer. When you fill up the second time the amount of fuel you put in is exactly what the car has used for the mileage on trip odometer, so it does not get more accurate than this. It also does not matter how much he gets out of tank, because 11.5L/100km is pretty bad if its mostly highway driving.

[eaybulut]

He is basing his 11.5L/100km on 75% fuel used. I know its not good for your fuel pump to completely run out and I also never mentioned resetting the trip odometer. Note that I also didn't say "do this every single time so you can ruin your fuel pump". The whole reason I suggested 2 trips as opposed to 1 was because it will give an average consumption. 1 week you could be driving fast.. the next week he could be going slow. So, basing it on 2 tanks full of gas and dividing total km driven by the total gas input in order to attain an average is definitely a better choice than just filling up... getting x km and saying I'm getting poor mileage, especially when its based on 3/4 of a tank used. My reason for suggesting so was as I stated above.. I seem to be getting the most mileage on the last bit of fuel in the system. This may or may not be the case for everyone. He can choose to do it or not, he's smart enough to make that decision..

[r4BBiT]

You probably get the most of the mileage out of the bottom of the tank because you drive more conservatively. I know I do that; when I'm low on fuel I don't ride as hard and watch my fuel gauge more often. So this would again be driving style. I'm pretty sure car's ECU does not know that the fuel tank is low on fuel and takes less fuel as a result.

If you want an average (valid point) over more kilometres then fill up few times and take an average of your result. I'm pretty sure that this is how fuelly works and how my dad and all of the people I know calculate their mileage.

[Stretch]

Yes, fuelly offers averages etc which is quite nice. I also like how it shows a month-to-month comparison too so I can see how my driving is affected by the weather/etc.
Get fuelly, monitor your fill ups, be merry!
eric

[eaybulut]

You probably get the most of the mileage out of the bottom of the tank because you drive more conservatively. I know I do that; when I'm low on fuel I don't ride as hard and watch my fuel gauge more often. So this would again be driving style. I'm pretty sure car's ECU does not know that the fuel tank is low on fuel and takes less fuel as a result.

If you want an average (valid point) over more kilometres then fill up few times and take an average of your result. I'm pretty sure that this is how fuelly works and how my dad and all of the people I know calculate their mileage.

Bud, I have no idea why... but I'm actually not going slower or accelerating slower. I have noticed, that no matter how hard I push down that pedal.. the car simply does not accelerate as fast as it does, compared to when there is 1/4 tank or more. I have, to this date, thought that this was some sort of feature of the car. :( Shows how little I know ..

[Dynames]

Havent considered going bone dry yet but we'll see what happens. Filled up today and its still 11.5L/100 so nothing has changed. Even when I drive what I call spirited, I'm hardly going over 3000rpm so really, its not like I'm going crazy here so there is definitely some issue. 11.5L/100 I might as well be driving a speed 3, I might get better fuel economy from it since its rating is exactly that, 11.5.

I took the car to simply tire to rule out any sort of tire problem which I had thought might have been an issue (bent rim etc), but I was told theres nothing wrong there. So now I have an appointment @ maple mazda and they are going to run some tests because frankly this is ridiculous. Love the car but theres no way it eats gas at this rate

[lawlzen]

is this an overpriced one or a good deal right now??

http://www.canadiantire.ca/AST/browse/4/Auto/AutoTools/AutoCodeReaders/PRDOVR~0251063P/Launch+Technology+OBD+Book.jsp?locale=en

Sorry I'm late to the party...
I've had a pretty good experience with an eBay OBDII Bluetooth reader.
http://www.ebay.ca/itm/ELM327-v2-0-Bluetooth-Wireless-OBD2-OBDII-Interface-Diagnostic-Scanner-Car-Tool-/261097219010?pt=Motors_Automotive_Tools&hash=item3cca9b63c2&vxp=mtr
That's actually the cheapest price I've seen because I bought mine for approximately $20.00. Shipping was decently fast too considering its free (approx. 1.5 weeks).

Works great if you just need to retrieve the codes. I've used it with the free Torque app on my Android phone.
Alternatively, you can pair it to your laptop if you have bluetooth there and use a more advanced program to do various other things.

[loosecannon]

Update:

I just seafoamed a few days ago and since then, my mileage has improved. I lost my first bar at 80km as opposed to 35km before I seafoamed. I'll update again when my gas light turns on and my next tank.

[eaybulut]

Holy sh*t ... that much of a difference? Thats absolutely amazing. Is it true that you have to seafoam every few months or at least once a year though? Or have I heard a lot of b/s ?


Update:

I just seafoamed a few days ago and since then, my mileage has improved. I lost my first bar at 80km as opposed to 35km before I seafoamed. I'll update again when my gas light turns on and my next tank.

[Booter22]

maybe once a year or if anything every two years.

[loosecannon]

Update:

I just seafoamed a few days ago and since then, my mileage has improved. I lost my first bar at 80km as opposed to 35km before I seafoamed. I'll update again when my gas light turns on and my next tank.

Update to this update:

My girlfriend borrowed my car today when I had two bars left at 480km. When she returned the car, she had filled up 3/4 of the tank. I asked her if the gas light turned on and at how many kilometers; she said she didn't notice. At least I know that my car had improved at least 50km in mileage since seafoaming. Doesn't sound like much, but to me, every little bit helps.

[Kiyomi]

Havent considered going bone dry yet but we'll see what happens. Filled up today and its still 11.5L/100 so nothing has changed. Even when I drive what I call spirited, I'm hardly going over 3000rpm so really, its not like I'm going crazy here so there is definitely some issue. 11.5L/100 I might as well be driving a speed 3, I might get better fuel economy from it since its rating is exactly that, 11.5.

I took the car to simply tire to rule out any sort of tire problem which I had thought might have been an issue (bent rim etc), but I was told theres nothing wrong there. So now I have an appointment @ maple mazda and they are going to run some tests because frankly this is ridiculous. Love the car but theres no way it eats gas at this rate

take it to redline and properly break in the car. :D <--- youd think im joking, but no.

[instict911]

on my 04 auto 2.3 L i get 440 km per tank 60% city 40 highway and a pretty heavy foot sometimes.

[JPJPJP]

Update to this update:

My girlfriend borrowed my car today when I had two bars left at 480km. When she returned the car, she had filled up 3/4 of the tank. I asked her if the gas light turned on and at how many kilometers; she said she didn't notice. At least I know that my car had improved at least 50km in mileage since seafoaming. Doesn't sound like much, but to me, every little bit helps.

I am going to give seafoam a try, and I'll post my results as well

[loosecannon]

I am going to give seafoam a try, and I'll post my results as well

Note: I only put seafoam through my intake vacuum hose with the red clip (whatever that hose is called).

I referred to this video as reference:


http://www.youtube.com/watch?v=hagmHV_nmWY

[JPJPJP]

Note: I only put seafoam through my intake vacuum hose with the red clip (whatever that hose is called).

I referred to this video as reference:


http://www.youtube.com/watch?v=hagmHV_nmWY

Lol.. Looks more complicated thn I thought. Someone live around 401/Leslie, or mccowan/Lawrence or meadowvale/Shepard that could lend a hand?

[Stretch]

It's really not complicated JP, for my speed, I just took the vacuum hose off the brake booster and had my girlfriend hold the idle up as I sucked Seafoam from a container. Only needed pliers for the whole thing.
eric

[silverstarmazda]

i personally use the seafoam spray. which is the same as the canned version... but in an aerosol form. sprays directly through your intake. both ways work and gets fed through the same place. i just have difficulty having the results last....

[brucewayne]

Lol.. Looks more complicated thn I thought. Someone live around 401/Leslie, or mccowan/Lawrence or meadowvale/Shepard that could lend a hand?

hey i haven't done the seafoam yet but ive been looking into it as well as PEA cleaners. im willing to meet up and help but i don't know how im gonna help... i just wanna see the smoke in person :P

mcc/law is best for me btw but whatever. have seafoam? will follow

[silverstarmazda]

since out cars have an electrical throttle body. it requires 2 people

[JPJPJP]

hey i haven't done the seafoam yet but ive been looking into it as well as PEA cleaners. im willing to meet up and help but i don't know how im gonna help... i just wanna see the smoke in person :P

mcc/law is best for me btw but whatever. have seafoam? will follow

I'm going to pick up seafoam later today. But now we need one other person that knows what they're doing, because I have no clue what to do either lol.. Anyone else can help seafoam my car at mccowan and Lawrence? I can help do yours too, since it apparently requires 2 people.

[JPJPJP]

**Update.. So I put in the fuel injector cleaner last fill up, and I've been tracking my consumption on fuelly. My average for about 1.5 tanks so far is 9.7L/100km. Which is actually a lot better than what I thought I was getting. I drove til the gas light went on. I travelled 414kms.. I thought it was pretty low. But when I went to fill up the tank. It only took 41 L to fill the tank. Meaning there is approximately around 12-14 L left of gas left in the tank, based on the 55L tank.

[GSXi]

I'm going to pick up seafoam later today. But now we need one other person that knows what they're doing, because I have no clue what to do either lol.. Anyone else can help seafoam my car at mccowan and Lawrence? I can help do yours too, since it apparently requires 2 people.

can i come and watch :p? may want to seafoam mine after winter.

here's my 2.5L (i only started keeping record since april; think my fuel-econ is taking a dump due to colder weather tho; hopefully improves again in summer):
https://dl.dropbox.com/u/88468769/fuelly.jpg

[loosecannon]

since out cars have an electrical throttle body. it requires 2 people

What? I did it myself. You're supposed to "let it soak" for at least 10 minutes while the car is off, then start it back up and commence the smoke show.

PS. I didn't use the spray. I had the same bottle as the guy in the video I referred to.
I guess the spray requires two people?

[eaybulut]

lol, I'm considering doing mine too. Is tomorrow an option since it pretty much gets dark close to 5:30pm ?

Like everyone else that is "considering" doing it -- I too have never done it. Mr. loosecannon can we do it under your guidance.. since you would be considered a pro at it, compared to us newbies ?

[eaybulut]

I just realized ... I'm not even considered a newbie.. I'm still a noob.

[loosecannon]

lol, I'm considering doing mine too. Is tomorrow an option since it pretty much gets dark close to 5:30pm ?

Like everyone else that is "considering" doing it -- I too have never done it. Mr. loosecannon can we do it under your guidance.. since you would be considered a pro at it, compared to us newbies ?

LOL sure. You guys pick a date and time and I'll see if I can make it. I live in Markham. Work in Brampton.

[JPJPJP]

can i come and watch :p? may want to seafoam mine after winter.

here's my 2.5L (i only started keeping record since april; think my fuel-econ is taking a dump due to colder weather tho; hopefully improves again in summer):
Yeah, feel free to watch lol.. So I've got 2 people watching.. Anyone wanna come by that knows how to do this though? Lol

[JPJPJP]

We should have a seafoam meet in an empty parking lot, then blow all our smoke away at the same time. That would look pretty sick :chuckle

[eaybulut]

LOL sure. You guys pick a date and time and I'll see if I can make it. I live in Markham. Work in Brampton.

Perfect! I'm in Richmond Hill and work in Markham.

In regards to the "seafoam meet in an empty parking lot and blow all the smoke at the same time "... $5 says someone is bound to call the cops. lol.

[loosecannon]

Perfect! I'm in Richmond Hill and work in Markham.

In regards to the "seafoam meet in an empty parking lot and blow all the smoke at the same time "... $5 says someone is bound to call the cops. lol.

I did mine in a parking lot. I had some guy come up to me while I was blowing all my smoke and said, "too much oil?" *facepalm*

[silverstarmazda]

seafoaming the engine will cause the rpms to drop. its okay if u can keep it from stalling but i rather have someone behind the wheel keeping a steady rpm to suck in the seafoam. if there isnt enough airflow, it ends up collecting at the bottom of the manifold and dries. one of the reasons why i use the spray because it "mists" and is easier for the product to make it to the engine.

i seafoam 100km before an oil change. i did mine on a friends driveway and got the whole street to come out and wonder wats going on LOL. i might jump on this cuz im almost at my 5000km OCI

[aris]

seafoaming the engine will cause the rpms to drop. its okay if u can keep it from stalling but i rather have someone behind the wheel keeping a steady rpm to suck in the seafoam. if there isnt enough airflow, it ends up collecting at the bottom of the manifold and dries. one of the reasons why i use the spray because it "mists" and is easier for the product to make it to the engine.

i seafoam 100km before an oil change. i did mine on a friends driveway and got the whole street to come out and wonder wats going on LOL. i might jump on this cuz im almost at my 5000km OCI


You put seafaom in your car every 5,000km??

[silverstarmazda]

You put seafaom in your car every 5,000km??

nope, i still have 1 can of sea foam spray from a couple oil changes ago. i use half per oil change...but lately i havnt used it since i didnt have a second set of hands. i use the seafoam spray, not the one that comes in the bottle.

[brucewayne]

nope, i still have 1 can of sea foam spray from a couple oil changes ago. i use half per oil change...but lately i havnt used it since i didnt have a second set of hands. i use the seafoam spray, not the one that comes in the bottle.

dude ill help you seafoam. i want to see that stuff work. ive thought about using it but i dunnoo

[silverstarmazda]

dude ill help you seafoam. i want to see that stuff work. ive thought about using it but i dunnoo

lol maybe in two months wen my next oil change comes up lol

[baymoe]

I'd like to watch. I have a can of the stuff in the garage, just too chickensh!t to do it myself lol

[silverstarmazda]

I'd like to watch. I have a can of the stuff in the garage, just too chickensh!t to do it myself lol

another reason why i use the spray instead LOL. cant imagine pouring something down a vacuum line....just doesnt feel right lol

[Ozil]

another reason why i use the spray instead LOL. cant imagine pouring something down a vacuum line....just doesnt feel right lol

I did it :D it was fun. Engine stalled like twice though

[brucewayne]

dang it! we need a seafoam party! we'll call some strippers and ill bring vodka

[baymoe]

Anyone doing it anytime soon? I'd like to participate. Coffee?

[2012Sky]

Does anyone here use TorquePro on an Android Tablet?

You can have that with you under the hood to eye the RPMs and keep them at a steady 2000 while pouring the Seafoam.

One hand on the throttle cable while the other pours. :D

[Booter22]

Does anyone here use TorquePro on an Android Tablet?

You can have that with you under the hood to eye the RPMs and keep them at a steady 2000 while pouring the Seafoam.

One hand on the throttle cable while the other pours. :D

car has an electric controlled throttle body. so there is no cable to pull.

[2012Sky]

car has an electric controlled throttle body. so there is no cable to pull.

I'm learning today. :D I really haven't been under the hood of my Mazda much to get a good look around.
Every other vehicle I've owned had cable controlled throttle.

[geobur]

car has an electric controlled throttle body. so there is no cable to pull.

ah...that would be why I could never find one...I always wondered because I like to know where it is so that if I need to rev it while looking at the engine I can, I looked and looked and looked but never found it...now I know why haha

[speedvision3]

my 2012 2.0L 2nd gen got 98km for the first 3 bars how bad is that ?

[loosecannon]

my 2012 2.0L 2nd gen got 98km for the first 3 bars how bad is that ?

Seems legit.

[speedvision3]

its never been that bad in the summer i got 100km for the first bar not first 3 ?

[loki]

At 260kms and gas light is about to come on

[Ozil]

At 260kms and gas light is about to come on

that made me feel better

[silverstarmazda]

car has an electric controlled throttle body. so there is no cable to pull.

also not recommended that the rpm should be kept up electronically while sea-foaming. so for the mazda 3, its a 2 person job.

[peterm15]

also not recommended that the rpm should be kept up electronically while sea-foaming. so for the mazda 3, its a 2 person job.

If the 3's throttle body is electronically controlled, wouldn't that mean even of you have someone step on the gas, the rpm is still be kept up electronically? To me that statement ( assuming its written on the sea foam package) would mean its no good for the 3.

[silverstarmazda]

If the 3's throttle body is electronically controlled, wouldn't that mean even of you have someone step on the gas, the rpm is still be kept up electronically? To me that statement ( assuming its written on the sea foam package) would mean its no good for the 3.

lol i meant by a scangauge or something. anything through the obd is bad. i forgot why, but i think it had something to do with rpms and pedal position. the ecu learns that its running at 2000rpm when the pedal is not depressed.

using the pedal (manual or electronic) or the throttle cable is fine

[peterm15]

lol i meant by a scangauge or something. anything through the obd is bad. i forgot why, but i think it had something to do with rpms and pedal position. the ecu learns that its running at 2000rpm when the pedal is not depressed.

using the pedal (manual or electronic) or the throttle cable is fine

Ok gotcha.