I am having a problem with my 93 Hyundai Scoupe base model. It has been revving to 4000 rpms while idling and then will drop to under 500 rpms, sometimes stalling the car. Recently, it has been stalling while driving as well. I will remove my foot from the gas pedal and be rolling with the clutch pushed in and the car will die, to the point where it will also kill the power steering. The car will not start for 20 to 30 minutes after that. I have a feeling it might be my alternator, but I am not sure. Any ideas?