Car shakes while idling

[Sinisa]

Hey I was wondering if anyone was having the problem I have.

My 2005 Mazda 3 GT sedan shakes while I am at a red light or when I am stopped and the engin is still running. It shakes once every 20 to 30 seconds and the RPM jumps to 1000rpm from 500rmp.

Did anyone eles have a problem like this or might know what is wrong?

[EvilEric]

You are not alone:

http://www.torontomazda3.ca/forum/sh...ght=rough+idle

http://www.torontomazda3.ca/forum/sh...ght=rough+idle

http://www.torontomazda3.ca/forum/sh...ght=rough+idle

Depending on how bad the shaking is, it could be a variety of possible things.

People have looked into Motor mounts, not pressing brakes hard enough, brake problem, need oil change, etc etc

[notoriousb]

Hey I was wondering if anyone was having the problem I have.

My 2005 Mazda 3 GT sedan shakes while I am at a red light or when I am stopped and the engin is still running. It shakes once every 20 to 30 seconds and the RPM jumps to 1000rpm from 500rmp.

Did anyone eles have a problem like this or might know what is wrong?

exact same problem I had , it ended up throwing a code eventually it was a misfire -- changed spark plugs it was gone.

[Sinisa]

exact same problem I had , it ended up throwing a code eventually it was a misfire -- changed spark plugs it was gone.

About how many KM did you have on ur car when you changed them?? I am at about 84000km

My check engin light also came on now!!

Hopefully new spark plugs will fix the problem!!

[TheMAN]

if it's doing the rpm bouncing, then I'd try replacing the spark plugs first... if it still doesn't fix it, it maybe a bad ignition coil

make sure you replace the plugs with the mazda ones.... they are NGK iridium plugs that last a long time and to make sure the car runs right

[notoriousb]

About how many KM did you have on ur car when you changed them?? I am at about 84000km

My check engin light also came on now!!

Hopefully new spark plugs will fix the problem!!

yeah mine is around 50 000.

[Sinisa]

Turns out the solinoid vacume pump wasnt working propertly! got that replaced and now the car runs perfectly!!

[Go_Habs_Go]

nice! glad to hear you got it worked out.

[trademark83]

I wish I had found out about this vacuum pump problem earliar, my warranty just expired. My car hasn't stalled again, only happened once, but I have seen the low shaky rpm.

[zedtech]

I've been having the same problem even after a spark plug change. I gotta look into this solenoid. DId you get it replaced under warranty?

[Sinisa]

No I just went to a mechanic I knew because Mazda wanted me to pay for them to check it again before they fixed it.

The part cost about $130 plus tax i think.

[jcutner]

im getting this again on my car

before, it was some hose or something that went into the stock airbox, but since it was fixed, the stock airbox is gone, and there is a CAI, and it seems like the shaking is resurfacing

[Darkfrosty7]

i had this and i replaced the engine mounts and it was fine after that

[jcutner]

i had this and i replaced the engine mounts and it was fine after that

how much does it cost to do this? and did you go with aftermarket (stronger?) mounts?

[rawbz]

i'm wondering how serious the shaking you guys experienced is? I have an 09 with only 19,000 km on it and have been experiencing something like this since practically day one.

Its not all the time.. maybe when the car is colder but it seems to just shudder every so often at red lights.

Asked the dealership about it and they said its just the car trying to run as 'lean' as possible.. is what you guys experienced a lot worse than what I'm describing? at least my car has never stalled from the dips in revs..

[CanSpeed 3]

Ive had this same problem for nearly a year. Got so bad my rpm dipped so low it actually stalled but kicked back up before it died completely, but only at a stop. Seemed to be worse if you were driving, then made a dead stop (red light). So today i went and bought a new purge valve from mazda 139.99 plus tax. Must be called the solinoid vacume pump to some. Idles better now. Easy to install yourself.

Any questions please pm, do ont get mazda to install it yourself if you have a set of wrenches at home

[TheMAN]

it never is always the purge valve
a throttle body clean should be attempted first as they have been known to stick and cause stalling issues... also an ECU flash update has been out to help alleviate that problem

[CanSpeed 3]

Cleaned a week ago

it never is always the purge valve
a throttle body clean should be attempted first as they have been known to stick and cause stalling issues... also an ECU flash update has been out to help alleviate that problem

[BoostieMonster]

i'm wondering how serious the shaking you guys experienced is? I have an 09 with only 19,000 km on it and have been experiencing something like this since practically day one.

Its not all the time.. maybe when the car is colder but it seems to just shudder every so often at red lights.

Asked the dealership about it and they said its just the car trying to run as 'lean' as possible.. is what you guys experienced a lot worse than what I'm describing? at least my car has never stalled from the dips in revs..

I have the same thing man, not a Rough idle as my RPM's do not change, just like you said, a slight shudder at the light. Its funny how everyone is getting different reasons from the dealership. One says "oh they're all like that don't worry", another says "trying to be lean", another says "The engine is just working in", "program needs updating".

[Google]

Ditto here as well. I've had it off and on since I got my 3. It appears certain conditions need to be present but I havent nailed them down. I've also had situations where the car would want to stall/die at a stop or red light. Dealer always comes back with No Fault Found. I'll just have to put up with it as I've got just another year or so before I trade my 3 in for something else.

[RNUOVR]

Chances are it's the purge valve - that was the case with mine - my car sounded like it has a .600 lift cam in it, almost stalled at every light, no CEL, nothing. I spoke to a local dealer who told me that they rarely clean out the throttle body as it's very rare that it's the cause of hte rough idle. I was told that 85% of the time this issue arrises it's the front Purge Valve. I cleaned out the Throttle Body never the less as I had the car in my buddys heated shop. I also swapped the plugs out, mine had 80k on them & the dealer told me that I could go to 120k on them, but after swapping out the purge valve on friday there was still a slight miss in the car that cleaned right out after swapping the plugs.

[Google]

In my case, it wasn't that constant. The dealer did clean out the throttle body under warranty. I never got the warranty paper on that. How long did it take you to clean it out? I imagine it must be a PIA process and expensive.

SInce mine isn't constant and the dealer isnt able to recreate the problem, they wont replace the purge or egr valve.

[urbanjoe]

Chances are it's the purge valve - that was the case with mine - my car sounded like it has a .600 lift cam in it, almost stalled at every light, no CEL, nothing. I spoke to a local dealer who told me that they rarely clean out the throttle body as it's very rare that it's the cause of hte rough idle. I was told that 85% of the time this issue arrises it's the front Purge Valve. I cleaned out the Throttle Body never the less as I had the car in my buddys heated shop. I also swapped the plugs out, mine had 80k on them & the dealer told me that I could go to 120k on them, but after swapping out the purge valve on friday there was still a slight miss in the car that cleaned right out after swapping the plugs.

Agreed. Mine had the same problem and it was the purge valve. Once I put a new one in it stopped shacking and the RPM where a lot smoother.

[Woodman316]

My 09 20,000 runs great.

[m_bisson]

this also happens if the freon in the a/c is at the wrong pressure. In the defog mode the a/c automatically turns on and off, causing the RPMs to spike or stall the car.