My 2001 Isuzu Rodeo Sport (65k miles, auto transmission) sometimes revs up and down (from 500 to 2000 revs/min) while idling in Park. When it does this, putting it in Drive causes it to shudder as if it's going to stall, but once it gets going, it runs fine.
<br/> This doesn't happen every day, but it doesn't seem to be related to the temperature. And it only happens after the car has sat overnight. I fear that this portends bad things to come. I imagine that the gears may be slipping, but am not sure. I have recently had a transmission flush, but that doesn't seem to have made any difference.
<br/> Any idea as to what might be wrong?