Your car is supposed to idle at 2000 rpm when it is cold. When your car starts, it should idle at 2000-2500 rpm for about 10 seconds, then you will hear a definite drop of about 500 rpm, when the dashpot closes. The car then will idle at that rpm, 1500-2000 or so, slowly dropping until the engine warms up and the hot idle is 800. Your car is doing exactly what it's supposed to be doing - it does this so that it will warm up and go into closed loop faster. You can close off the IAC thermal valve if you wish, with mechanic's clay or similar, but then you will have to do what the IAC does, ie keep the idle high with your gas pedal. Car will bog until its warmed up otherwise.
Yes the initial idle for first few seconds is high with the fast idle dashpot, problem is with the dashpot energized, the idle is almost 3000. After it retracts my idle is still over 2K and the engine has to be within about 10degrees of full operating temp before it will even start to drop. I have even replaced the T-stat with a 195 degree. My initial thoughts were that the stat was either stuck open, or incorrectly installed or the wrong one was used etc.
I have chased all of the other possible vacuum leak sources, and eventually got to the point of trying the clay trick, which is where the idle finally responded the way it should, ie have to use foot to keep engine running when cold.
I just want to make sure I don't inadvertently damage something when I remove the valve for inspection/ replacement.
You cannot remove the IAC as it is part of the throttle body, you can only block it up. If your car is idling at 800 rpm when the engine is warm, then chances are you have no vacuum leaks. I think you can buy the IAC with the bottom part of the throttle body - very expensive, however. You can remove the plate to the IAC and look at the valve itself, making sure that it doesn't stick which carefully pushed in, and carefully cleaning around it so that it operates properly. There is also a screw behind the dashpot that you can adjust counter clockwise to reduce the idle down from this 3000 rpm, that might help.
Okay, this particular 94 air valve has a different adjusting nut with two partial holes approx. 11/16" apart. I had to make a crude tool to remove/adjust it by cutting two "pins" into a piece of 1/2" EMT then spreading them slightly. Had to work it in & out with PB blaster to get it to operate smoothly.
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Thanx for that info! I have been too busy at work to try out your suggestion yet but when I do, I will definately put up a post to let others know about this trick if they are suffering from the same problem.
I can say that my adjustment ring nut is the multiple point job as shown in that link you sent me.
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