Pontiac Problems? Ask a Mechanic for Answers ASAP
Hi There, I'm Clayso a certified master automobile technician with 30 years of automotive repair and diagnostic experience.
From your description sounds like an ignition misfire under a load. How old are the plugs,wires, cap and rotor button?
Let me know
That's cool. Have you verified fuel pressure?
Fuel Pressure Key On 40.5-47 psi Idle 30.5-44 psi
A cracked flywheel would definity cause a vibration. Automatic or manual?
Cool. Unbolt the torque converter and push it back into the transmission. Start the engine and see if you still have the vibration. Also with the torque converter back you can flex the flywheel, might even be able to see up to the flywheel bolts. Flywheels usually crack around the bolts to the crankshaft.
This would also eliminate the torque converter as a possible cause also.
There's always the vibration damper on the front of the crankshaft to consider, as long as it's coming apart or separating it should be ok.
You're welcome. Let me rephrase, as long as the vibration damper is not coming apart, and I'm sure the timing has been checked and being that the timing mark is on the damper I'd say it's ok.
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Just checking to see if you found the vibrations source. Let me know.