Idle surge ???

[dormeas]

Okay I know this is a common topic so bare with me I'm new. I have a 1991 Eagle Talon (just bought) and when I start the car cold it will idle kinda fast....probably normal. But once it warms up the idle goes up and down between like 1000-1600rpm. Sometimes it will stop varying for a minute and stay high or low but always goes back to the annoying rev up and down thing.

So is this the idle surge everyone posts about all the time? I unhooked the TPS while it was running and it did not make any difference. I have tried to inspect for vacum leaks and appears to be fine. I just figure I need to replace the IAC or ISC whichever it is called. Any info would help.

 

[EagleTSIawd]

yep, its a vacuum leak. you have to check all your lines including the brake booster line that feeds off on the back of the manifold. You should also inspect your intake manifold, cracks or a bad gasket could also cause this type of symptom

 

[dormeas]

Well looks like it's fixed... in a last ditch effort I never thought would work, I removed the BISS changed the O-Ring, set the idle to 750 and......no more wierd idle issues. Thanks for the help thought sure it was a sensor. Boy would that have been a waste of money.


Phil

 

[hockeyguy44]

I had a simaler surging problem but recently it stopped and my turbo started sounding weird shortly after that after the car comes into opperating temp it idles down and dies will start back up fine and run with higher rpm (1991 talon tsi fwd) i was thinking IAC or TPS but not sure???

 

[EagleTSIawd]

I had a simaler surging problem but recently it stopped and my turbo started sounding weird shortly after that after the car comes into opperating temp it idles down and dies will start back up fine and run with higher rpm (1991 talon tsi fwd) i was thinking IAC or TPS but not sure???

your turbo makes a weird noise? check for any play in the turbo