I've found during my extensive engine-out refresh that the idle control valve was stuck open. The rotary valve won't move by hand or by 9V of persuasion which explains the high warm idle. But now I wonder, does the IAC have any control over the return to idle? When I used to drive this thing (ah, memories), the millisecond you released the throttle and hit the clutch, it dropped back to idle making smooth shifting tough.

My last few cars have been new enough to have the emissions friendly throttle overrun in the ECU so at first I wondered if it was just because it was an old car, but thinking about it now it still seems like it should be a softer landing.

So, how quickly do your cars drop back to idle?

 

I never noticed this particular problem, however I've noticed mine tends to drop and "bounce" very low before it ends back at the proper idle...a couple times it's bottomed out completely and stalled, although not recently. There was some talk about whether it was this valve or not...I never came to a conclusion either way, I got in the habit of goosing the gas pedal slightly when pushing in the clutch and preparing to come to a stop. I never noticed difficulty shifting smoothly, however.

 

in order for the ISV to work the TB needs to be at the idle setting (the TPS idle switch is closed).