07 Mazda 3 Misfiring with no CEL

[Axela3]

Need some direction on where to go from here. I have a 07 Mazda 3 with the 2.3L manual. I have been having issues with misfiring while driving/idle but the Check Engine Light is not coming on to give me a code. I have done a lot of forum reading on this but still have no direction on what to do.
At 100,000kms I changed from the stock plugs to E3's. Had issues misfiring right after changing them do to a faulty plug. I got a new set of E3's and problem went away immediately. I now have put 107,400kms on them without issue but started having trouble a few days ago with misfiring again. I put the stock plugs that had no issues back in but still had the issue so I replaced them with new NGK Iridium XP's. The issue seemed to be resolved for about 10kms then back again. I know some forums have been bashing E3's and Bosch saying that the 2.3L Mazda doesn't like them which is why I replaced them with new NGK's as everyone has been recommending. There has been a lot of talk about plugs and coil packs being the issue but no direction on what to do when your not getting a trouble code and still have the issue.

Anyone having or had this same issue, and what was the solution? I do have a CAI and MagnaFlow exhaust but they are the only engine mods that have been done and have been on the car for over 10,000kms without issue. :bang

[Axela3]

So I've bench tested all my coil packs with an ohm meter and they are all reading the same. Checked all the plugs, they are all burning perfectly and even throughout cylinder 1 thru 4. Checked for vacuum leaks, obstructions in the CAI, filter and hoses to find everything looking spotless and new. Took off the TB to look for buildup but nothing. I ran some intake cleaner thru the TB, and MAF sensor but it's still kicking.

I see alot of threads about coil pack #3 being their CEL code but no one has yet to find a solution?

[Booter22]

why dont you take it to a dealer and have them inspect the car. could be pending cels. but as your are fixing and replaceing them your not giving the computer enough time and drive cycles to put the light up. seems you have spent enough time and money trying to run around and chase it yourself. why not go spend 100 bucks or an hour of shop time and have someone with the right computer and training look at the car and fix it right. otherwise you could throw coils at it. wiring. maf sensors. oxygen sensors and a whole bunch of other time guessing on what it is.

[Axela3]

Pending CELs, that does make sense. I've only run 12kms since disconnecting the battery when I put my plugs in, worried about getting stranded with a lowered car that can't be towed. I've been avoiding the dealer cuz the CEL wasn't on yet and my code reader wasn't picking up anything. Will they be able to read a pending code that my scan tool won't? I'd hate to spend the $100 bucks and have them tell me nothing.

I was also thinking that my CAI might be an issue now that the temperature has dropped. I'm only driving in the early am and late pm after working on it throughout the day???

[silverstarmazda]

drive it around untill you get a light. then go to part source and check the light for free! but itll probably tell you something stupid obvious like "codeXXXX engine misfire". hopefully itll tell you something more in-depth. E3's in general are just crap. nothing but advertisements and fancy designs that dont work. your still getting that one arch because in the end, you still have one ground on the plug. intake cleaner as in throttle body cleaner? dont use that on the MAF. throttle body cleaner has something in it that prevents it from eating away at the teflon coating inside the throttle body. not sure if that leaves a residue, but its kinda why theres a special cleaner for the maf/electronic connector because they leave no residue

[peterm15]

Certain OBD2 readers will tell you detailed info about the cylinders. Honestly it means nothing to me BUT if running it it may tell you if there is problems and what cyl it's in. You do not need a code to run these tests.

[silverstarmazda]

Certain OBD2 readers will tell you detailed info about the cylinders. Honestly it means nothing to me BUT if running it it may tell you if there is problems and what cyl it's in. You do not need a code to run these tests.

and if you start getting into the really expensive scanners, you can play with all kinds of stuff on the car lol. (not recommend) such as controlling certain aspects of systems and changing timing temporarily.

[Flagrum_3]

So I've bench tested all my coil packs with an ohm meter and they are all reading the same. Checked all the plugs, they are all burning perfectly and even throughout cylinder 1 thru 4. Checked for vacuum leaks, obstructions in the CAI, filter and hoses to find everything looking spotless and new. Took off the TB to look for buildup but nothing. I ran some intake cleaner thru the TB, and MAF sensor but it's still kicking.

I see alot of threads about coil pack #3 being their CEL code but no one has yet to find a solution?

You've checked the coil packs for resistence and said they show fine, zero ohms I assume? If so, you can rule out the coils as the issue. You've used three types of plugs and the issue persists, so that eliminates the plugs as the cause. You've eliminated vacuum leaks and your TB, dirty or not, would not cause misfiring. Does your scanner have the ability to scan and record as you drive? This needs to be done, its the only option and as I would suspect the issue is further up the channel from the coils and can be several things causing the issue.

_3

[silverstarmazda]

probably has something to do with fuel delivery?

[Axela3]

First off, I'd like to thank everyone for their input. You all make good points that I was too frustrated to think of yesterday. The battle still continues but I'm looking into the fuel system now. Thinking back when this all began, my fuel light was on and was probably 30km into the light. The next morning I fueled it up and dumped a bottle of fuel system cleaner into it. I've barely driven 20kms since so I'm hoping I just need to run a tank thru it and clean out the fuel system. I did take it for a spin this morning without issue but it was only 10km.

[Booter22]

Pending CELs, that does make sense. I've only run 12kms since disconnecting the battery when I put my plugs in, worried about getting stranded with a lowered car that can't be towed. I've been avoiding the dealer cuz the CEL wasn't on yet and my code reader wasn't picking up anything. Will they be able to read a pending code that my scan tool won't? I'd hate to spend the $100 bucks and have them tell me nothing.

I was also thinking that my CAI might be an issue now that the temperature has dropped. I'm only driving in the early am and late pm after working on it throughout the day???

there is times when there will be a pending count and waiting for enough counts to set the light off. which = a pending cel. sometimes pulling the battery wont clear or reset those codes. and if scanned with an aftermarket scanner and then a dealer scanner it may delete the codes in the system which i have also seen happen.yes if there is a pending code in the system then yes it would come up on the scanner. intake should run better once cold more cool air in the engine. worst case call the mazda dealer by you to ask if they will charge you if there is not code in the system.

[silverstarmazda]

First off, I'd like to thank everyone for their input. You all make good points that I was too frustrated to think of yesterday. The battle still continues but I'm looking into the fuel system now. Thinking back when this all began, my fuel light was on and was probably 30km into the light. The next morning I fueled it up and dumped a bottle of fuel system cleaner into it. I've barely driven 20kms since so I'm hoping I just need to run a tank thru it and clean out the fuel system. I did take it for a spin this morning without issue but it was only 10km.

its all about the adventures of car ownership lol. might be bad quality gas, or a failing fuel pump. the farthest i want to run my car after the fuel light comes on is 30km. but i have been forced to go up to 45km. not sure how far the car will go but i always try to keep it under 30km. $20 is only enough to fill a bit less than 3/8 of the tank when gas prices are 133.5. which sucks because i can use to get about half a tank with $20.

try to put the cleaner in first before you fuel up. the fueling action helps mix the cleaner. i use to use lucas fuel injector cleaner with upper cylinder lube. but now im thinking of just using the motormaster stuff from canadian tire. heard some good things about them so ill give it a try.

[Axela3]

Well I think I've finally found my issue thanks to sheer dumb luck:headbang
So I'm just about ready to give up and take it to Mazda. Before I was going to take it in I wanted to put the original plugs that I changed for sheer maintenance at 100k. I put them in and was running the car just to see if it helped. I had my ratchet sitting on the battery box when it kicked once and sputtered. The ratchet fell off the battery box and hit the MAF sensor wiring and the engine went into convolutions! I picked up the ratchet and got it started again, then it came to me. I jiggled the MAF sensor wiring around and got the engine to die. Tried once more just to make sure my nightmare of a weekend was over something so simple.
A few months back my CAI came off the frame mount and dropped to the skidplate, I bolted it back up and no issues at this point. I guess over the past few months of working it back and forth the CAI had stretched the wiring and finally got to the point I'm at now. Something so simple yet invisible to the naked eye. I'm going to order a new plug tomorrow and we'll hopefully be able to get my baby back to life and ready for the Heart for Hearth photo shoot on Sunday.

I'll post my findings once I change it and let you all know.

[silverstarmazda]

Well I think I've finally found my issue thanks to sheer dumb luck:headbang
So I'm just about ready to give up and take it to Mazda. Before I was going to take it in I wanted to put the original plugs that I changed for sheer maintenance at 100k. I put them in and was running the car just to see if it helped. I had my ratchet sitting on the battery box when it kicked once and sputtered. The ratchet fell off the battery box and hit the MAF sensor wiring and the engine went into convolutions! I picked up the ratchet and got it started again, then it came to me. I jiggled the MAF sensor wiring around and got the engine to die. Tried once more just to make sure my nightmare of a weekend was over something so simple.
A few months back my CAI came off the frame mount and dropped to the skidplate, I bolted it back up and no issues at this point. I guess over the past few months of working it back and forth the CAI had stretched the wiring and finally got to the point I'm at now. Something so simple yet invisible to the naked eye. I'm going to order a new plug tomorrow and we'll hopefully be able to get my baby back to life and ready for the Heart for Hearth photo shoot on Sunday.

I'll post my findings once I change it and let you all know.

lol congrats! and it was a free fix!!