When I am traveling at approx 50-60 mph on a slight incline, I notice that the AT can't seem to figure out what gear it wants to stay in. I can feel it step down and step up within seconds until I either reduce my speed or simply increase until I am over 60 MPH on the same incline. Is this sign of a sensor failure? It always happens when the A/C is on, but I am not certain if there's a connection there, as in making the engine work harder on that same incline and interfering with the operation of the AT shifting gears. Thanks in advance. DB