95 GST Rough Idle

[tinydancergst]

Okay guys, just bought my first DSM a few weeks back and can't figure out what the deal with it is.....

Basically, I think I have a vacuum leak because it starts and runs, and runs great at-speed, but just won't idle right..it will surge from 750-1400 and everywhere in between. I replaced the IAC valve and I've checked damn near everywhere for leaks but just can't find any! I need a little help....

ANDDDDDDD! The cruise control won't hold the car at speed but it will accelerate it????

 

[mrmitsu]

You say you checked for leaks...I assume you did a boost leak test.

Also, have you tried adjusting the BISS?

Throttle bodies are notorious for leaking at the shaft seal.

 

[tinydancergst]

You say you checked for leaks...I assume you did a boost leak test.

Also, have you tried adjusting the BISS?

Throttle bodies are notorious for leaking at the shaft seal.

I haven't any idea how to do a boost leak test..

And yeah the BISS helps but I can only get the rpm down to around 800 and it'll continue to surge and such.

 

[gusu]

Idle surge? I'd start here.

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

It could still be a leak as well.




How to test the ISC as well. http://www.youtube.com/watch?v=KibYz21IMA0

 

[Abe'sGST]

Try cleaning your throttle body as well, it's very easy and effective. Also since you just bought it, check your plugs and wires.

 

[tinydancergst]

I replaced the ISC already as a precaution..I got an EGR blockoff plate also and I'm gonna put that on tomorrow...I'll try the rest of the suggestions as well and let you guys know what happens. Thanks!

 

[Abe'sGST]

Word of advise, try not to change parts without verifying that they are the problem. Also before taking anything apart, grab a can of brake cleaner and spray around your throttle body and intake manifold and see if the idle changes any. Afterwards clean out your throttle body and see if it helps.

 

[tinydancergst]

Word of advise, try not to change parts without verifying that they are the problem. Also before taking anything apart, grab a can of brake cleaner and spray around your throttle body and intake manifold and see if the idle changes any. Afterwards clean out your throttle body and see if it helps.

Figured new parts are a good thing.

Alright guys..screwed around with it all morning and now it literally sits at "idle" at 2k rpm..is that a problem with the throttle position sensor???

Also, I used the Ohm meter on the TPS and the resistance was in tolerance levels..but it didn't change (resistance) when I turned the throttle.