My car has developed a clicking noise that i can only hear when im on the gas and moving. While driving if I take my foot of the gas the noise goes away. Cant hear the noise at idle or when parked reving the car. car still runs fine and shifts fine but does feel a little rough at highway speeds. motor sounds nice and healthy and the exhaust note has not changed. oil is full, just changed last week. Just cant seem to track down the noise....any ideas? thanks