Well my 1990 STE is having some more problems.  When I start it up it idles normal, however as soon as i put it into gear the idle will raise up to about 2500-3000. Thus meaning the car will accelerate itself rather quickly without me touching the gas. However as soon as I slow down or get near coming to a rest, the idle usually falls back down to normal.  I have just replaced the plugs, wires, and 02 sensors.  I have checked for vacuum leaks and there are no major ones, definetly not enough to cause this sort of thing.

My only other thoughts are bad ecu or possibly a clogged cat, but i don't think the cat could create this sort of a problem. Does anyone else have any ideas?

check your fuel injectors for leak down and or low resistance readings on a voltometer.  I believe anything under 12 ohms is considered spent.

other than a massive vacuum leak I would think that would be the best place to start.

What chip are you running?  Have you ruled out the cross over pipe?

could it be an IAC valve gone wild?

     Or have you went through the search sections under Idle high. I just look through there and their is a solution pertaining to this particular problem

           http://www.tgpforums.com/index.php?topic=3969.0

I am running the stock chip.

I have ruled out the crossover, as it appears to not be leaking.

I have boost leak tested it, and there is a tiny vac leak that I haven't been able to track down, but would that not make it idle high all the time?

I also noticed that when it idles high, if i tap on the diaphram of the Cruise control enough to raise the idle, it will quickly fall back to to regular idle.

Thanks for the suggestions, i'll attempt to test the injectors.

Fixed it guys, replaced the injectors with some 99 GP injectors.  Idle fell back to normal like clockwork.  Thanks for the advice.

Well that fixed it for about two days.  Drove it for about a half hour this morning and by the time i got to my destination, it was idling/revving right back up there, maybe not quite as bad but still undrivable.

You have a vacuum leak somewhere or your cross-over is cracked causing a false lean. When it sees a false lean it will increase the fuel to the injectors. Then when it sees an incredibly fat mixture it will open the IAC to try to lean it out with fresh air.

Just because you do not see evidence of a bad cross-over does not mean it is not leaking. It is very hard to see a carbon trail when you have 1/2" of insulation and a heat sheild surrounding the cross-over.

I had a similar problem with mine and I changed the ECM and did an idle re-learn and it runs great now.