2.4L SE running badly [Archive] - GrandAmGT.com Forum


View Full Version : 2.4L SE running badly

07-19-2009, 06:35 PM
Multiple symptoms that may be stemming from the same problem. Don't know exactly where to start, but I'll do my best...

1. The car idles high. Regardless of the temp, the car idles around 2,500 rpm.

2. When I'm driving either in town or on the freeway and put the car in neutral (5-speed manual transmission) the engine revs to about 3k and stays there. When I come to a stop, rpm drops back down to around 2,500. This is regardless of how fast I'm going. If the car is moving, the engine is reving higher. The second I stop, revs drop.

3. Ocassionally "Service Engine Soon" and "Trac Off" lights will turn on and the car will start running very badly. If I pull up to a stop light the engine will die and it takes a lot of cranking to get it to start again. To keep it from dying while sitting at a stop light, I have to put it in neutral and pump the pedal. If I hold the pedal constant, it will die. I have an OBDII code reader, and when this happens it generates code P0502. If I park the car overnight, the next morning this behavior is gone, and no codes are stored.

The fast idle and high reving described above are consistently present, regardless of driving condtions, weather, which way the wind blowing, if I'm picking my nose, how many root beers I've had that day, etc.

I know P0502 means that the speed sensor could be dead. Can a dead speed sensor cause these other problems?

This is driving me crazy. Any suggestions???


07-19-2009, 11:48 PM
Speaking of these things, does anyone know the AC Delco part number for the VSS? The car is a 2001 Grand Am SE, 2.4, manual transmission. I can't seem to find the OEM part number.