high idle after warmed up

[SubaCraig]

I've searched and searched and couldnt find a thread with a solution to my problem.......when I first start my car in the morning it idles at @ 650 ..by the time i get to work it idles at @ 1800 in park. Basically the opposite of what it should be doing. I've cleaned the IACV and adjusted the TPS to .5v
is there something I'm missing?
-thanks in advance
-craig

[SoCal LS-L]

First make sure the screw on your throttle body butterfly valve isnt adjusted really far in, which will keep the butterfly valve open, then id inspect your auxillary air control valve, which controls your cold idle speed, it almost seems the connector could be hacked on backwards or something. Im not sure a failing coolant temp sensor would do this but its worth inspecting also.

Im sure more ideas are to come for stuff I cant think of at the moment.

[SubaCraig]

Well the AACV is not hooked up backwards and it quit doing it for a couple of days .........and it starts doing it again.......I can turn the engine off and restart it and it will idle right .....and sometimes it will shoot up to 1800 when I put it in Park and quickly work its way down to @ 650 .
could this be a transmission issue ......? or a sensor problem?

[processengr]

Well the AACV is not hooked up backwards and it quit doing it for a couple of days .........and it starts doing it again.......I can turn the engine off and restart it and it will idle right .....and sometimes it will shoot up to 1800 when I put it in Park and quickly work its way down to @ 650 .
could this be a transmission issue ......? or a sensor problem?

This is exactly what happened to both our '92 s. In both cases, it was the tps. Search the how tos, to test the tps for dead spots.

Also, my shift points were "funny" ie. would down shift unexpectedly, and 1st to 2nd were delayed then abrupt.