Revs up,drops down continuously

[JeroldsSis]

I have a 2003 EB Expedition with 32,000 miles. Today when my car was running while in park, it started revving up then would drop over and over again. When I drove it this way I could feel it while driving, as well. Not sure what may be causing this problem. It's the holiday weekend and I've parked it until I decided where to have it serviced unless this is something I can fix. Any thoughts on this matter would be appreciated.

 

[tonydiv]

The two things most directly related to idle speed are the IAC (idle air control) and the TPS (throttle position sensor)

There are, of course, several other items that could be at fault, but I think those two are your prime suspects.

You may just want to look around for any disconnected wires or vacuum lines first. You don't want to pay a mechanic $85 to plug in your mass airflow sensor wire harness.