My car has been to the local GM dealer eight times. When traveling at highway speeds of 55-65 mph. With the air conditioner on, ambient temperature at 60 Degrees or above and going uphill, the car surges. You can see the tach go up from 2000 to 2200 rpm and back. As soon as your on level ground car runs fine. The dealer has replaced plugs, wires, air filter, fuel filter and it hasn't changed. Also, it shows no fault codes. Please tell me what you think it could be. Thanks!
Oct 22, 2010 at 10:34 PM