2000 grand prix gtp

[tyntate]

I have noticed a vibration when accelerating, as if it is missing out. It has also stop running at different times when driving or at idle. At first when it died, it would start right back up, but lately, it turns over several times before starting. At no times has a " ses " been displayed. The car has about 150000 miles on it. And these problems started about a week ago. The shop has had the car for two days now, and it has not stalled on them yet. They did however say that it seems to be missing out when accelerating, and think that this might be in the injectors. Do I need a fuel pump? What psi does the pump need to run at? Or is it something to do with the ignition? Any professional help would be appriciated.

[BNaylor]

Check the fuel pressure first. Possibility of fuel pump, fuel pump relays, fuel pump resistor, fuel filter, or fuel pressure regulator. Fuel pressure readings on a GTP varies due to having two speeds for the fuel pump.

For ignition check the spark at the plugs. A flaky crank position sensor can cause stalling or hard starting.

Welcome to AF.

[tyntate]

Well my "great mechanic" has had me spend some money these past two weeks. We changed the plugs,wires,fuel pump,fuel filter, cleaned the injectors, and yesterday I changed out the pass. front hub assemby. They thought now the car was not missing, but vibrating due to a bad wheel bearing. It did have some "play" in it when you pushed and pulled on the wheel. We also cleaned the mass air flow sensor. Nothing has helped with the vibration when accerating, or the car dying. Same problems as before. They now want me to change out the computer. Is this a problem with the coil packs or ignition modual? It is getting exspensive and all iI want is my car to not vibrate or die. More help would be appreciated. Thanks.

[BNaylor]

It would help to better explain your problem and describe the noise. Is it a misfire feel or mechanical vibration? How does it sound and it is there only when accelerating?

Just a wild guess but you could have a flaky harmonic balancer since the engine is externally balanced and it may be affecting the crank position sensor causing the stalling.

[richtazz]

I agree bnaylor. Is your tach jumping around when it missing or dropping to zero just prior to it dying? If so, as bnaylor suggested, the crank sensor or harmonic balancer may be bad.

[tyntate]

It feels like a tire is bad when I am accelerating at higher speeds.(65-70) At lower speeds is feels more like a miss. It makes no noises at all. The tach will only jump if it stutters before it shuts off, but most of the time it will just die like you turned off the key and the check gauges light comes on. It also died the other night while I was in park waiting on some take out. It may go two days without shuttingdown or shut down every mile. However when it has set overnight, it seems to run better without hardly any vibration untill you get to higher speeds. Also afteryou have been driving down the road for a while, the vibration seems to be there only it is very slight. A week before The vibration started, I had the tranny fluid changed. And then two weeks after that is when it started shutting down. Like i said at first it only did it once a week and now it can happen at any given time. Let me know if this helps.