Mechanics

MISFIRE

2000 Pontiac Bonneville • 108,000 miles

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.
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Smalldarl
December 19, 2011.



Have you checked for a restricted exhaust yet?

Saturntech9
Dec 19, 2011.
HOw do I do that?

Tiny
Smalldarl
Dec 20, 2011.
With a good scan tool you should be able to see specific misfire counts on specific cylinders to help you isolate the problem.

Wrenchtech
Dec 20, 2011.
A exhaust shop can check your exhust back pressure for you.

Saturntech9
Dec 20, 2011.