'89 Corsica Trouble

Heya! I just registered, not sure where else to find the info on this problem I'm having:

When starting, the engine turns over just fine, but idles at a high speed to warm-up and slowly drops down to a normal idle. When in gear (whether Drive or Reverse), it will idle high for a bit and then return to normal.

Anyone have and idea as to what the problem might be?

Thanks!
~Alan

if i were you I would check the following - remove and clean the IAC valve(unhook the battery first, and do NOT push in on the pintle/spring). Spray it with carb/injector cleaner and gently clean the surface of the pintle, as well as the area it sits in. Check all vacuum lines for cracks/splits. Replace any suspect. Check the intake hose for splits/cracks, motor will not run right if there is any. Clean the throttle plate with injector/carb spray cleaner and runs a can of injection cleaner thru the gas tank. The car will need to learn idle so be patient and use proper idle learn procedure. Here is a link to a Corsica site where it is explained.

http://www.corsicas.com/