Ok I have a 95 Trans Am. Been running great till recently. When I have the clutch disengaged like say if I were going down a hill and didn't care about speed, My RPMs will stay around 1500 I don't get it they used to drop to idle around 800. My car also idles higher now at around the 1500 mark. The only things I have done to it are CAI and a cutout.

 

I was having all sorts of idle problems recently also.. the car idled high but only when it was rolling. I replaced the IAC and cleaned the TB but that didn't help much if any. I then found a wicked vacuum leak in the PCV system by spraying TB cleaner around the intake manifold.. that has since solved the high idle problem. I'd suggest you look for a vacuum leak and check the IAC (consider replacing - $50). Do a search for my user name and you can get an better idea of what I'm talking about.

I still have issues though.. the rpms drop really slowly and still sometimes stick (no, TB blades are not sticking and don't show signs of wear/play).. I think I may still have a vacuum leak some where else..

Seems like a lot of people have had similar idle problems recently. If I manage to completely solve the problem (maybe by finding another leak or whatever) I'll post about it. But right now all I can suggest is that you look for a vacuum leak and check/clean/replace the IAC.

 

How did you test for the vaccum leak? I'm not really up to par on that yet.