Got valve covers changed on my 2004 Grand Prix GTP. Ever since, my car hesitates at idle and in drive. I thought maybe the car was missing. The rpm guage jumps back and forth and car eventually shuts off. But I can keep starting the car and drive it around the nieghbor and eventually it will run fine like nothing was wrong. Took car to dealer and they suggested changing O2 Sensor, Crank Position Sensor, & Fuel Pump. I changed them all and the car still runs the same. I even changed the tempature control sensor and no luck. Has anyone had these problems before or does anyone know what the problem with my car may be?
