This thing is driving me crazy!! First I have a 1998 TJ, 4.0, 5-speed. I had a whistling noise, turned out to be intake gasket. Replaced that, then it started the HIGH IDLE problem. I have cleaned out the throttle body, installed a new IAC valve and new TPC, still idling high. I checked and could not find any vacuum leaks. The parts house people told me to disconnect the battery, to reset the computer, tried that and still no luck. It does idle down normal (750 rpm's) occasionally but nothing to say it is fixed. When it is idling high, it is around 1250 - 1500 rpm's. Like I said, it is making me go crazy!!