Mechanics

MULTIPLE CYLINDER MISFIRE

2000 Pontiac Grand Am

Engine Performance problem
2000 Pontiac Grand Am 4 cyl Front Wheel Drive Automatic 139000 miles

I have a 2000 Pontiac Grand am with 139000 miles on it, I was driving along and instantly it began running very rough with white smoke and raw fuel coming out of thr exauhst.I did a compression check and all cylinders are around 200psi. When I pulled the spark plugs #3 and #4 cylinders are flooded with fuel and appear that they are not firing.I replaced the complete ignition module/coil and wires and plugs, and also changed the entire fuel rail and injector assembly from a identical running car and still no change the engine does not knock or rattle just shakes very badly. When I plugged my code reader it showed a PO300 multiple cylinder misfire detected.
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Austinadill
March 13, 2008.



Need to get a " noid" light and see what the injectors are doing on the cylinders that have wet plugs (bright light flashing vs. Dim light flashing). Verify good spark at the plugs on these as well

Tiny
Jack42
Mar 13, 2008.