Bad Idle-When Stopped

ThunderCoupe94

Registered User
Wasup Guys? I just had a quick question. When i stop at a light or anywhere with my car in drive it has a bad vibration. Like the RPM's stay around 500 and it just idles bad. Does anyone know what could be the cause of this? I am desperate for your help i have tried everything. Changed the motor mounts. Asked the mechanic about it. Has anyone else had this problem? Let me know ASAP. Thanks in advance

Jay
 
Check these...

Is your Check Engine light coming on at all?

Run a code test, may point you in the right direction.

More than likely, it is the Idle Air Control Valve. This is what controls the idle speed (via signals from the EEC). Another trouble spot could be the O2 sensors. Does it do this all the time, warmed up or cold start? How does it run otherwise? Gas mileage?

Mor info..

Phil
 
Re: Check these...

phils89sc said:
Is your Check Engine light coming on at all?

Run a code test, may point you in the right direction.

More than likely, it is the Idle Air Control Valve. This is what controls the idle speed (via signals from the EEC). Another trouble spot could be the O2 sensors. Does it do this all the time, warmed up or cold start? How does it run otherwise? Gas mileage?

Mor info..

Phil

You just described my cars symptoms to a t.
 
More Info...

Phil, the answer to all your questions, It does it all the time warmed up or cold, Runs great other the the rough idle, and the gas mileage to a full tank is 200 miles i just tested that out. Anymore info would be appriciated.

Jay
 
My '92 SC done the same thing. I changed the O2 sensors and it helped some. But it still done it, the engine also stalled from time to time. A mechanic told me that the locking torque converter was not unlocking when I stopped at a light or stop sign. I just rebuilt my engine and had the trans rebuilt too, had a new TC put in and now my car doesn't idle rough when I stop. Might have the TC checked and see if that is the problem. might not be causing it but that is what I had trouble with.
 
Re: More Info...

ThunderCoupe94 said:
Phil, the answer to all your questions, It does it all the time warmed up or cold, Runs great other the the rough idle, and the gas mileage to a full tank is 200 miles i just tested that out. Anymore info would be appriciated.

Jay


*raises hand*

I have this problem too... I replaced the drivers side 02 (got a code for it) but still have the same problem, cleaned the MAF, same prob, reset the computer, got worse. But other than idling it runs strong I've had it die a few times when I'm stopped too, it'll idle for a while with 10in of vac which seems a lil low to me (high?) but I'm not sure....
 
N/m I found it... they had to remove the upper intercooler tube when they replaced the alternator, and when they did they didn't tighten the collar nut tight enough and it was loose... Vacuum Leak
 
All these things sound to me like a vac leak. Low gas mileage, rough idle, fine running, maybe slight loss of power.

If there is a strange howling when shutting down, then its an IAC.

Otherwise, I would check the vacuum system for inobvious leaks. They can be hard to find. The fact that it got worse after resetting the computer further indicates this, as it lost what it learned from the 02 sensors to compensate from the lack of an accurate reading out of the MAF sensor.. which would occur w/ a vac leak.

To reduce the possibility that it might be the auto transmission, shift to neutral & see if the symptoms remain.
 
SAME PROB AS YOU THUNDERCOUPE94

Can anyone answer this.

IAC.. can that be taken off and cleaned and put back on

also should you take a spray bottle with some soapy water and

spray around the IC connections as well as the Air assembly unit

to check for possible leaks because this happened to me right after my tune up and i think in an effort to put the components back on it might not be as tight as it could be
 
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