I have a 1998 3.8 Camaro and my idle is so screwed up i don't know what to do but want to fix it myself... Some things that it does is when i first start it i will die most of the time and then ill start again and it will just about die go to about 200 rpm and fluxiate between like 200 and 1400 or it will just keep diein unless i hold the gas down a tad, also sometimes ill start it and will idle at like 2500 rpm and not go back down for like ten or so minnutes even when im drivin at low rpm if i engage the cluth it will rise back up also when im shifting from gear to gear it will pause before it drops down to idle or actually rev back up a lil from where i first engaged the cluth...and then other times it runs just find, also will a new cluth fix when your drivin and accelerting my car will jump down like 300 or 400 rpm and jerk will hard what might be causing that any suggestions would be great thankyou....

What's the history on your car Andrew. Did you just do some work on it, or did this suddenly start happening recently? In the other 507 post I mentioned that you can connect the PCV line up to the wrong port and get this problem - though my experience with that phenominon was on a TPI motor. Same theory applies though.

The idle speed control circuit is a closed-loop circuit. The engine controller expects a certain amount of air to "leak" into the motor, primarily through the PCV system. The rest of the air is metered by the Mass Air Flow sensor (I believe the 98 3.8 is a MAF). If a vacuum leak allows air to enter the motor unmetered, the idle will surge up and down and even die.

If your engine has a MAF sensor, make sure the ducting between the MAF and the throttle body is properly connected. Some of GM's ductwork designs in those years was a bit hokey to say the least. It was easy for ducting to roll under, crack, or separate allowing air to enter the engine without flowing through the MAF sensor. A bad PCV valve could do it. A leak in the vacuum brake booster diaphram can also cause it. Perhaps this will give you some ideas.