Misfire

2000 PONTIAC BONNEVILLE
108,000 MILES
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SMALLDARL
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  • 2 POSTS
Have a problem with misfire. Took the car to O'reily's and ran diagnostics. Told code was for ramdom misfires. Changed plugs and wires, runs the same. Very difficult acceleration with a lot of noise and rattling, once running over 35-40, seems to run fine. Took back to O'Reily's, code again said ramdom misfire. Suggested coil pack. Changed one that appeared to have a bad stem on it, still the same problem. I'm lost. Service engine light solid when idling or accelerating, flashing when achieves 35-40 mph.
Dec 19, 2011 at 11:41 PM
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SATURNTECH9
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Have you checked for a restricted exhaust yet?
Dec 19, 2011 at 11:54 PM
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SMALLDARL
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HOw do I do that?
Dec 20, 2011 at 12:00 AM
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WRENCHTECH
  • CAR REPAIR CONTRIBUTOR
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With a good scan tool you should be able to see specific misfire counts on specific cylinders to help you isolate the problem.
Dec 20, 2011 at 12:25 AM
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SATURNTECH9
  • CAR REPAIR CONTRIBUTOR
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A exhaust shop can check your exhust back pressure for you.
Dec 20, 2011 at 12:39 AM