1997 Oldsmobile Aurora misfiring

1997 OLDSMOBILE AURORA
104,000 MILES • V8 • AWD • AUTOMATIC
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DANM24
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my engine light came on and the computer says i have a misfire on cyclinder 8 and i changed the spark plugs and wires and coil pack and it still has trouble starting and lights still on
Feb 22, 2010 at 8:57 PM
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ERNEST CLARK
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Instead of replacing components, test each component until you identify the source of your trouble.

The ignition system isn't the only thing that could cause a misfire. You could also have a lean misfire, or even a fouled plug.

One of your injectors could be bad, and not spraying enough fuel to ignite. Also, one of your injectors could be leaking and sending too much fuel into that cylinder, fouling that plug and preventing it from firing. Finally, you could have excessive oil leaking past the valve guides and fouling that plug.
Feb 23, 2010 at 4:57 PM
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DANM24
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well it was the fuel injector no codes come up anymore lights off cars running better but the car is still having trouble starting could it be the fuel pump
Feb 24, 2010 at 8:11 AM
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ERNEST CLARK
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  • 1,730 POSTS
Yes, you could have a bad fuel pump. The best way to check this is with a fuel pressure gauge. Compare your readings to spec.

Your fuel pressure regulator could also be faulty. If you're having starting troubles only after the car has sit for awhile, then that could be the FPR. If you're always having trouble starting, then the check valve inside the fuel pump could be bad.
Feb 24, 2010 at 3:45 PM