Can't locate a vacuume leak. Removed the IAC and cleaned it. Engine idles ok with the IAC connector off, but when reconnected idle goes back to 3000RPM. I will check the IAC voltage/resistance tonight, but I am wondering if you can drive the truck with the IAC diconnected without damaging anything??

 

Replaced the IAC: wasn't the problem. Checked the connector voltage as recommended in the manual. It reads 8.5 volts from the PCM, book says should be approximately 10.5 volts. Is that enough difference to cause a 3000 RPM Idle??