my brother has a 92 firebird that has a lopy idle it will idle up and down while driving and while sitting there... we are going nuts we thought it was the position sensor but we purchased a new one and not it check the egr and still no problems just replaced the oxygen sensor and still no luck him and i are pulling our heair out trying to figure this out any help would be great thanks

 

does it only happen when the car is warm, or does it do it any time? try cleaning out the idle air control, it's the little port with a connector with four wires on it, on the passenger side of the TBI unit. spray some carb cleaner in there while it's running, and see if it doesn't help. if it's really dirty, take the TBI unit off and clean it with a Q-tip.

 

I've also seen many computer controlled cars running cams with not enough LSA that will do that cuz it'd driving the computer crazy and screwing up vaccume levels.

 

I would make sure that you have a clean TBI unit and PVC valve. Take them off and clean them very well. There are tiny passages than can accumulate funk over time and not draw the right amount a vaccuum. Also, when was the last time you replaced the ful filter. A clogging fuel filter will cause idel problems yet remain smooth when cruising. Hwoa re your injector spraying? Are they an even triangle shape without any drips or spits?

 

This is a bump because there was an error that did not register my above post and bump the thread.

 

thanks guys i will check all of that and that should fix it it does it all times when it is warm or not and the injectors are spraying right:hail: