shaky idle on a Corolla S

[hadadat]

Hey all,
hadadat here, I've been lurking the forums a bit just getting myself acquainted with everything, figured I'd sign up and make a post.

So, I have an 03 Corolla S. My problem is that whenever the engine is idle, at a red light, warming up, whatever, I have a rough idle. My car shakes, and then stops, then is starts shaking again. I thought it might be the cold air induction so I put a new filter on, and nothing. So whenever this happens, as soon as I apply the slightest pressure to the gas, it stops. I know a bit about cars, but of course on a diagnosis like this I'm not sure what to think. I have a warranty but the dealer wants to charge to look at it. Any help is appreciated! tty all soon

[Mins]

Try cleaning the MAF sensor, sometimes that helps.

[ToyotaMan1281]

could be bad plugs and wires/

[mince_23]

hi, i noticed the same problem on my girlfriends 03 corolla today. i'm an apprentice mechanic and was having a look around because she's said its been idling roughly and a little shakey sometimes.

upon having a look i noticed a sucking/air leak sound coming from around the plastic intake manifold towards the ports. thought it could be a crack or something in the plastic manifold under cheap/poor design maybe.

i also checked for the noise when opening the throttle slightly, and it stops... let it go, and when it reaches idle speed again, the sucking sound starts again. so possibly either an air leak from the manifold only under full vacuum of idle, or something playing up in the idle speed/air controller.

but to contradict myself, when i open the throttle slightly then let it go, that generally makes for a stronger vacuum in an engine (if it had a vac gauge hooked up), so the noise should techincally be stronger/louder on engine deccel.

also i'd doubt the MAF would be clogged up already, or spark plugs fouled etc. hers has only done 45,000kms (about 28,000 miles)

so for the moment i'm stumped, but i suppose someone else might be able to help.

Thanks!

[05_Echo]

Originally Posted by mince_23

hi, i noticed the same problem on my girlfriends 03 corolla today. i'm an apprentice mechanic and was having a look around because she's said its been idling roughly and a little shakey sometimes.

upon having a look i noticed a sucking/air leak sound coming from around the plastic intake manifold towards the ports. thought it could be a crack or something in the plastic manifold under cheap/poor design maybe.

i also checked for the noise when opening the throttle slightly, and it stops... let it go, and when it reaches idle speed again, the sucking sound starts again. so possibly either an air leak from the manifold only under full vacuum of idle, or something playing up in the idle speed/air controller.

but to contradict myself, when i open the throttle slightly then let it go, that generally makes for a stronger vacuum in an engine (if it had a vac gauge hooked up), so the noise should techincally be stronger/louder on engine deccel.

also i'd doubt the MAF would be clogged up already, or spark plugs fouled etc. hers has only done 45,000kms (about 28,000 miles)

so for the moment i'm stumped, but i suppose someone else might be able to help.

Thanks!

Try spraying a little WD-40 at the area where you hear the sucking noise, if it goes away then you know you have a leak or a cracked vacuum line.

On the risk of sounding dumb do these cars have a Idle Air Control vale (I.A.C. valve)? My 94 Crown Victoria had a problem with the I.A.C. and it did the very same you are describing with your Corolla.

[mince_23]

ahh ok, yeah i was thinking about doing the carby cleaner trick, but didnt want to do that on a plastic manifold incase it attacked the plastic, wd-40 is a good idea though. will try that tomorrow.

i'm not sure where the idle air control valve is (probably does have one) but its another thing to look for - might be clogged up from too much idling

thanks for your quick reply!!

[05_Echo]

Originally Posted by mince_23

ahh ok, yeah i was thinking about doing the carby cleaner trick, but didnt want to do that on a plastic manifold incase it attacked the plastic, wd-40 is a good idea though. will try that tomorrow.

i'm not sure where the idle air control valve is (probably does have one) but its another thing to look for - might be clogged up from too much idling

thanks for your quick reply!!

No problem..

[JeffG]

My 02 does this as well. I have new plugs and have cleaned the MAF...
BTW the IAC Valve is located on the bottom front of the throttle body...

[93V65spdcamry]

I have an 06 rolla S, same problem. Mine is more vibration, mass air sensor seems to really go beserk at idle...
Im really not impressed with mine so far. Bought it brand new. It has headliner noises, shaky idle, rough starts. Dealerships always give runarounds for warranty work. I had a 93 Camry V6 with 300k on it that sounded and acted smoother. I worked at a toyota dealership in oakville when i bought it, EVERY corolla on the lot idled the same.
It really sounds and feels like it struggles for air or oil pressure

[shoes1382006]

i think it just the intake manifold! cuz its plastic that what makes it so noisy and prolly make sound like its rough!

[run2erun]

I have the same problem on my '04 Corolla. I'm no mechanic, but couldn't this also be the signs of a bad motor mount?