RPM varies while driving
While driving at 60 mph the engine rpm will jump up a couple hundred rpm then drop back down. It will do that constantly. What might be causing it?
It could be your IAC (Intake Air Controller) that is stuck in the open position which could explain the RPM's jumping around. Try removing it and spray cleaning it and then reinstalling. Make sure however that it is moving freely after the cleaning otherwise the issue will still be present.