I had to screw the throttle stop screw to turn up the idle after my car would stall after decelleration or idling in drive or changing gears from park/reverse to drive and back. So now when I start the car, it idles at about 700-800rpms (i know the car should be able to handle 500rpm idles but for some reason mine would stall) When I shift into drive, it idles at about 600-700 rpm which is better.

The problem is when i shift back to park after driving, it idles at about 1200-1300rpms and never goes back down.

 

inspect IAC and possibly clean passages in TB as well as IAC?.

 

in my attempts to fix the stalling problem that was occurring before I changed the throttle screw, I removed the IAC pintle and cleaned it (as thoroughly as i thought possible) and put a little synthetic lubrication (for bearings and such) on the pintle's shaft.

Though i suspect it's a problem with either the pintle or the motor in the IAC that is causing my problems. It doesn't seem to be able to catch up when i'm braking as the engine will sound like it's surging and the rpms will jump up as i'm decreasing a couple times before settling at idle.

 

Could also be problems in the vacuum lines. Check all the hoses for integrity.