High Idle: Cleaned IACV With No Luck

[Thoughtful_One]

I cleaned the IACV on my 1992 240SX the other day. What was strange was that my IACV did not have that brass screw covered in epoxy. Anyway, I dismantled the unit, removing brass colored solenoid and I cleaned all of the carbon deposits. I figured that this would have fxed my idle, but when everything was in place, it did not help at all. I even placed dielectric grease on the connecters. I followed the procedure that the FSM said to adjust the idle, though when I disconnected the TPS then started the motor to manually adjust the idle through the screw, the idle shot up to 2000 and stayed there. With the screw all the way in, the lowest I could get it down to is 950. Also, sometimes it will idle at 850, but then there is an audible *pop* noise and the idle goes up by 150 RPM. When the car is in neutral when coming to a stop, the idle shoots to 1200 and stays there until I fully stop. When revving the motor, the RPM's, when falling, fall very slow when the throttle is closed, and very gradually come down to 950. Any suggestions?

[Thoughtful_One]

The most logical thing to do would be for me to test the TPS I suppose.