I have a 97 SC2 and when I come to a stop the the engine wants to idle
at around 2000 rpm, then it drops down to about 1500 for a short while
eventually it will drop back down to normal.
I just pulled the throttle body off and cleaned it, I took out the IAC
valve and cleaned the carbon off the end of the pintle, reinstalled
everything and the car still does the same thing.

Could I have a bad Throttle Position Sensor?

No codes by the way.