idle surge??please help!

[93eclipse4g63]

My car idles just fine at idle. When i stop at a stop sign or anywhere after moving, my car the idle on my car kinda goes on the fritz. it will rev down to normal, then rev up a few hundred rpms then back down, and repeats about 3 or 4 times. This just started, and i have been driving the car daily for the better part of a month. any ideas??? any insight would be greatly appreciated... thanks

p.s. the car is a 1992 eagle talon TSi FWD if that makes any difference(stock)

 

[GSX93DSM]

Most of the time it is caused by the air idle control valve. Under the throttle body. That would be my guess. I wouls alo check for leaks around the throttle body. Spray some soapy water onto the throttle body and everywhere you think it could leak air out. Least this way you not it is not a leak.

 

[oldman]

Is your BOV vented?

 

[tw21987tsi]

there is a temp switch on the throtelbody and if that is nop good the ilde will surge when the car is cold and there is a idle screw on the top of the throtelbody that may be out of place try to tighten it a little that might do it

 

[oldman]

there is a temp switch on the throtelbody and if that is nop good the ilde will surge when the car is cold and there is a idle screw on the top of the throtelbody that may be out of place try to tighten it a little that might do it

1. Welcome to tuners. You must not have yet read through the site rules, all tech posts must follow proper grammar, spelling, punctuation and capitalization. You don't need to be perfect all the time but this is as bad as I have seen in a while without web speaking.

2. There are no temperature switch on the throttle body, there is however a FIAV, fast idle air valve, that can affect idle after warmed up.

3. There are specific procedure that must be followed when adjusting the BISS (Base Idle Speed Screw), you can't just turn the screw.

 

[1LE]

Mine does the same thing. When it's cold out my O2 sensor doesn't stay warm enough while decelerating to a stop. I come to a stop and the car makes a mess of the fuel trims while trying to get the O2 sensor readings correct. Takes several minutes of idling for heat to get in the O2, then for the fuel trims to find the right values again. Idle surging the whole time. Very annoying. Started doing this after I removed the A/C condensor.

 

[93eclipse4g63]

umm i don't think my bov is vented, everything under the hood is stock so far..... umm as far as the temp goes, it does it at temp not when it is cold... thanks for the advice so far, i will try those things and let you know my updates

 

[RSTurboFWD90]

To cure idle surge, start by cleaning the throttle body including the ISC. Read this to get a better idea of the other possible causes.
http://www.dsm.org/how-tos/tttt/tttt3.html
It seems to me that no amount of logic will enable you to pinpoint the problem and fix it quickly. My car has had idle surge several times over the last 16 years. It comes and goes and acts differently at times. As long as it's drivable I just live with it. Good luck.