2001 Tauras with a bad idle

This is a problem that just started to show itself recently and is becoming more and more of a nuisance. It doens't matter what gear I'm in, whether its park, drive, neutral or whatever. Whenever I come to a complete stop the idle drops suddenly and then jumps up again and it will continue to do so until I start moving again.

Now I don't have the slightest idea of where to start. I figured that I would try some injector cleaner, but that did nothing. No check engine light or any other indicator light has come on to tell me that I have a problem.

Any help would be much appreciated.

Look at the Idle Speed Control Motor. Sounds to me like it is not responding quickly enough to the sudden drop in rpm's.