my 91 gs has an idling problem it jumps up and down from 2 to 1500 rpms. and ive replaced it with 3 different sensors so what else could make it do this.

 

check for vacuum leaks that would be a real good start to finding the problem. Maybe even plugs and wires.

 

vacuum test on what, i was going to change the spark plugs but ran out of money... lol

 

It could just be that your adjustments are off or that you are adjusting it incorrectly. Remember, there's a CTP switch that needs to be adjusted BEFORE adjusting the TPS. From there you can adjust your idle base settings.

Joel, CA

 

also check your altanator belt, mine slips when it's loose and runs bad.

 

do u have an aftermarket bov?

 

my bad ist a gs nevermind

 

Does it run rough or does it sound like it's hunting? (Like someone is revving the engine up and down)

 

you have idle surge. tell us what youve tried to replace to far. Possibilities are a bad isc motor, idle adjustment is off, bad egr, dirty tb, missing/bad vacuume line. no matter what it is, it will be located around the tb

 

ISC? I'm guessing you mean IAC motor? That was what I was thinking it is...