misfiring 2001 grand am

2001 Pontiac Grand Am

so far they replaced the catalytic converter, fuel pump, fuel filter, and cleaned fuel rail. Engine compression is 160 across all four cylinders. New plugs, coils and  igntion module. Could it be a sensor? vehicle has 70,000 miles and oil changed every 3,000  thanks.

2 thoughts on “misfiring 2001 grand am”

  1. The most common issue with the Quad 4 Engine is Plastic Piece the coils mount in(this is called the ignition coil housing). Replacing this should cure the misfire. Extremely common for this engine. When this part fails it allows the spark to arch and you can’t see it as it is covered from view.

  2. thanks your diagnosis was 100% correct spark actually bored a hole right through the plastic damn,could of saved $808+tax thanks to you!

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