Driving to work as normal and took off from a full stop when all of a sudden the car was going nuts trying to catch a gear. Service engine light blinked than stayed on and now when driving between 1st and 3rd gear car sputters, shakes, slams into gear hard and I need to keep giving it gas to get it to catch so I move and don't get stuck in the middle of making a turn. It is a 99 Grand Prix SE 3800 engine sedan and I brought it to my good friend who owns a shop and the computer said it was a C1 misfire solenoid or something like that. On my engine, the left side has 3 things that 2 spark plug wires goes into each and are labeled 1/3, 2/5 and 4/6 (might be wrong on numbers). The code was saying the first one that says 1/3 was bad causing the misfire. We changed the part and the service engine line went off and car drove fine. The next morning I went to go work and at the first light, I go to take off and it starts shaking and sputters and becomes almost impossible to drive. During this the service engine line blinked than stayed on steady. Now the car has trouble catching a gear from 1st to 3rd and it feels like a roller coaster just trying to take off from a stop or during heavy traffic. I replaced everything else on the car and give up with problems. There has to be a defect that Pontiac won't admit.

- Wantagh, NY, USA