[mightymoose_22]

You most likely need a new Idle Air Control valve. The IAC is about the size of a couple D cell batteries and sits atop the intake manifold at the throttle body. I believe it costs less than fifty dollars and is a simple do-it-yourself job as it is only held on by a couple of screws. Some people have gotten away with just removing it, cleaning it, and lubing a bit, but because of the low cost and simplicity to replace I would suggest putting a new one on.