Ok, Ive posted up about this before but have yet to solve the issue. I got to do a little more diagnosis today as I drove through the mountains on the way home from Knoxville. The problem: After driving for about 3 hours or so my car starts to hesitate when I press the accelerator and then kicks in and then kind of jumps while the accelerator is depressed. No CELs are set nor does it blink when the problem is present. It becomes more dramatic on up hills and today it completely shut off going up hill while still having a little more than half a tank. I waited about 5 minutes and it started back up and would accelerate but the problem still persisted. I let the car sit for about an hour while I ate lunch. I filled the tank and started driving and the problem had gone away completely and the car accelerated normally. Daily driving the problem is non existent only during extended driving. I think it may be the fuel pump. The car has almost 170,000 miles on it with Im assuming an original pump. I think the pump becomes over worked and can no longer deliver the fuel needed but I don't understand why it returns to normal after sitting unless its heat related. Anyone have an insight on this/seen this problem before? Any help would be greatly appreciated.