Hi, after doing a fair amount of research I was convinced to change out the IAC (Idle Air Control) valve on my 1993 Ford Explorer 2WD 4.0L. My vehicle showing ALL these symptoms but ONLY after about 10 seconds at idle WHEN auto transmission at Drive setting (normal drive): a. entire vehicle - rock slight back and forth at idle b. volt guage rock back and forth about 2 to 3 volts from "normal' c. drop in RPMs from about 800 to 500 - feels like the vehicle is about to stall... move the car to N (neutral) and the problem abates by about 20% move the car to Park and the problem abates to about 30% replacing the IAC (where the old one tested electrically ok) didnt fix anything, sad to say. Wasted $60. Check Engine Light is not on. Car runs very well EVERY time it is not idling for longer than about 3-10 seconds. Ie, as long as engine RPMs are above about 1000 rpm, this vehicle runs fine. Ive also read that my vehicle's issue could be related to the MAF. If so, is there any danger to checking whether or not it is the culprit by simply removing it ? Any suggestions ?