A couple of times I've had the engine just about quit on my '05 GT when shifting down to 3rd or 4th to pass on a highway; it didn't stall, but there was a deadly pause. I had it checked by the dealer, then decided I was revving too high in between gears, cutting power by the rev limiter. But... in the last few days I've noticed an occasional severe hesitation after running a distance at highway speed, as if the engine were hot, tho the guages tell me otherwise... Acceleration is rough, kind of bucking, or the same near stall. Anyone else or any ideas? Many thanks.