2012 Mustang GT Misfire

2012GTCS

New Member
Oct 4, 2020
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New York
Looking for help on my misfire issue i've been having on my 2012 GTCS. I am getting misfires on cylinders 2,4,7 and 8. I have checked spark plugs coil packs and fuel injectors already. Have no idea what is causing it. Any help is appreciated.
 
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Noobz347

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When you say that you checked the coils, what does that mean exactly?

How about the plug wires? Have you opened the hood in the dark with the engine running? Do you notice any arcing anywhere?

Codes: What codes do you have?
 

Noobz347

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replaced all the coil packs with new ones
havent checked plug wires
codes: po302 po304 po307 and po308

Ok good. It's a running joke around here about the number of coil-pack that are purchased [new] and do not work.

Try swapping your old coil packs into the positions of the misfiring cylinders and let us know what you find.
 

kiddiccarus

The first widely accepted Tranny
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Dec 24, 2003
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  1. Determine 1 good coil pack hence NOT the ones that are listed as a misfire.
  2. Clear the Codes
  3. Move the 1 good coil around to where the misfire is at. (ONE at a time)
  4. Start the car and wait for the CEL to pop up again.
  5. Replace the coil (remove the test coil and put in a new coil.)
  6. Clear the codes
  7. Wash- Rinse - Repeat
 
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Noobz347

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As a side note: The majority of aftermarket coil-packs are junk:
Nd9GcSK-vTm_wGkdptq8jX9q7RVqiDtWhiw7TCSpw&usqp=CAU.jpg


Nd9GcQuzv09ylXVOG1NesjUN1a4AnfirAfppuejaA&usqp=CAU.jpg


Stick with the OEM units. All but one in my Suburban have lasted 250,000 miles. :shrug:
 
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Benparker

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May 18, 2019
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Looking for help on my misfire issue i've been having on my 2012 GTCS. I am getting misfires on cylinders 2,4,7 and 8. I have checked spark plugs coil packs and fuel injectors already. Have no idea what is causing it. Any help is appreciated.
So I went down this road with my truck (2V 4.6) thought I had a coil that went bad and changed them all only to discover that I had a coolant leak that was causing the issue. The plastic intakes are prone to blowing the gasket and the coolant gets into the plug hole and shorts out the spark. Check the coil boots for moisture when cool. Mine also had an internal leak that put coolant into the intake furthering the misfire but the external was the root of the misfire.
 

cbxer55

Active Member
Jan 25, 2020
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Lets see, shall we. I have had ACCEL Super Coils in my 98 V-6 Ranger for so many years, I can't recall. Put them in my 07 Mustang when I was facing P0300 Random Misfire, along with hew wires. Fixed it right up. I've used Accel's in my vehicles all the way back to the late 70's, never had an issue with them. I know quite a few old time hot rodders that use MSD coils in their rides, never heard of one of them complaining about them.

I think companies like Accel and MSD should be able to sue you for LIBEL for saying that crap! Maybe I'll send them both an email with this thread linked in it.