Warm Weather = Rough Start-up


I have recently purchased a 2002 VW Passat. The car has 51,000 miles and is in excellent condidtion. But - I have noticed that when the outside temperature is 80 degrees +/- or warmer the car starts rough or will not start without using the gas pedal. This occurs when engine is both cold or hot. When temps are between 75 and 80, car starts but with an every so slight hesitation. And finally when temps are below 75, car starts perfectly. Any advice would be greatly appreciated…


The computer receives signals from sensors for both air and engine coolant temperature. My guess is that one or both sensors is providing incorrect information to the computer. This could be as simple as a bad electrical connection, or it could be a bad sensor. The sensors can be tested.