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Unread post by Guest » Sat Jul 24, 2021 4:38 pm

03 Pontiac montana, 3400.changed all six spark plugs,started ran drove fine untill it warms up then starts missing and dies.could that be coil packs or the module?

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Re: Ignition

Unread post by carriedi » Sun Jul 25, 2021 4:50 pm

It could be. why did you change the plugs? Was it doing this and you changed the plugs and you still have the problem or did the problem only happen after the new plugs were installed?

Have you scanned it to see which cylinders are missing?

If you can find out which cylinders are missing then you could swap the coils around and see if the miss follows the coils or does it stay with the cylinder. you could also do that with the plugs and see if it is a plug problem. What did you gap the plugs to?

does it miss all the time after it warms up, or just at idle, or just on acceleration, or just on cruise?

does your check engine come on? or is it on when you start up your car?

If you can find someplace that has a graphing scanner you could watch the scanner and see what happens when the engine warms up. Sounds like it could be a closed loop problem. When the engine warms up and the computer takes full control of the engine systems it reacts to a bad input some where.

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