1996 F-150 idles high

Engine idles high to where it accelerates up to 30 miles an hour after letting of the brake and after shutting the truck off after driving a few miles and try starting it back up, I have to hold the gas pedal to the floor to start it at times. But truck starts right up every morning no problem. When I step on the gas pedal it stutters for a split second and then revs up.



I have cleaned the throttle body, mass air flow sensor and replaced the air idle control, replaced the throttle position sensor, and replaced the PCM. Even the little things like fuel filter and air filter are new. When I unplug the IAC connector the engine idle drops to normal. I can’t figure it out.