Engine fast idle when AC on

[220richard]

Please help. I have a 2001 Ford Explorer 4wd 4.0. Almost every sensor/regulator are new and the gas tank components are new. I have performed the idle adjustment as outlined within the forum and cleaned the throttle and injectors. The Air filter is also new.

PROBLEM: The truck starts and idles fine with or without the AC on. With the AC off, if I accelerate the RPM jump up stay up for a bit but find 700 again. When the AC is on and I rev the engine (in park or while driving) the engine revs and stays up (about 1500 RPM) eventually finding 700 RPM again. To fix this, when I come to a stop I just turn the AC off. With the AC off it takes less than 3 seconds for the engine to idle at 700 RPM and then I turn the AC back on. Once I accelerate I start the sequence all over. MAF, IAC, EGR, EGR sensor, PCV, TPC, O2 sensors, fuel pump, fuel pump regulator sensor, fuel pump regulator, fuel filter, air filter all new.

When it is running high the MAF reading goes way up on my diagnostic computer so I am guessing it is working properly. The IAC ohms correctly.

Any suggestions would be most appreciated.

 

[220richard]

IAC bad even when new and ohms

The new IAC was faulty. I cleaned the old one as directed on this forum, swapped them and now it is running fine. I will replace the old one having read that cleaning it helps but it's still probably going to go out soon.