i have a 2001 1500 3.9L V6 Ram with 60,000 miles on it. it runs fine, but theres a problem. it idles way too high when in Park. it throttles up to 1500-2000 rpms but when put into Drive, it stops and idles at 500 rpms. the spark plugs, spark plug wires, air filter, and distributer cap have all been changed. but it continues. my father and i have narrowed it down to a couple different things...either a vacuum leak somewhere or the o2 sensor is not properly working. need help!

 

Grab a throttle body gasket from the parts store. (they are like 2 bucks...) pull the throttle body off, and take the IAC motor out. It bolts to the back side of the throttle body. Clean the pintel, and the passages in the tb. (have the battery disconnected while you are doing this) Put it back together, see what happens. If that doesn't help, couple possibilities are the IAC motor itself is bad, or tps.