Mutiple misfires

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2007 PONTIAC GRAND PRIX
6 CYL
2WD
AUTOMATIC
149,000 MILES

Car has code for multiple misfires. Engine light flashes when you drive it. I checked plugs and wires. Found a cracked coil pack. Replaced coil pack still runs rough. I troubleshot some more and this thing is running only on two cylinders. There is no spark at two of the coil packs. The one I replaced has no spark. Swiped coils a round and only the middle one has spark. I am thinking ICM. Just want to make sure because that is a $130.00 part.

Saturday, August 3rd, 2019 AT 4:10 PM

3 Replies

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

Here is excerpts from the factory diagnostic troubleshooting guide for Direct Trouble Code(DTC) P0300, which is the DTC for a Random/Multiple Misfire(s). Please go through it and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros

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Saturday, August 3rd, 2019 AT 8:22 PM

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I installed a new ignition control module today. She startes right up and I am pretty sure she is firing on all 6 now. Test drive went good still have a flashing check engine light going to have the codes. Cleared at the auto parts store tomorrow and she what comes back.

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Sunday, August 4th, 2019 AT 4:26 PM

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello again,

Just follow the Repair Verification instructions on the last diagram that was sent to you and you should either be okay, or know where you stand, but it sounds good to me. Please keep us informed.

Thanks,
Alex
2CarPros

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Monday, August 5th, 2019 AT 1:31 AM