Its a 99 Pontiac Grand prix GTP supercharged. It changed all of a sudden with the load noise and then barely made it home.
It started about 4 weeks ago. Engine light came on telling me cylinger 1 misfire after a hard weekend of driving. As long as I didn't stomp on it you wouldn't know there was a problem. When you went to pass, car would not accelerate. I changed the spark plugs, wires, air/fuel filter and light went out but power was the same. Going home one day I stomped on it and then there was a loud growl and then the car would only go 30 miles an hour. Once you RPM's reach 3500, the car just dies. There was a grinding noise from the supercharger so I changed the supercharger with a rebuilt and still the same. Changed camshaft sensor,crankshaft sensor, and mass air flow sensor and nothing has changed.
I have disconnected O2 sensors and it does not make a difference. I have scanned it many times and it usually just comes up as mis fires. It seems to idle fine but as soon as you rev it up over 3000 it begins to die and the back on the motor smokes.
Please help
Thanks
