Weird off idle stumble/miss

Discussion in '2005+ Mustang GT 4.6L Tech' started by ghunt81, Jul 19, 2021.

  1. ghunt81

    ghunt81 New parts on old junk! S197 Team Member

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    I ordered a set of coil packs tonight so gonna try those and also check out the plugs. The plugs literally have a couple hundred miles on them at most, I can't believe there would be anything wrong with them.
     
  2. DieHarder

    DieHarder Member

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    You said it yourself. It's the only thing you've touched recently. When troubleshooting (especially electrical issues) I always check/suspect the most recent work I've done. In my experience if it was running fine the problem is usually something I've worked on, added, changed, or replaced. Parts can go bad but rare. Still, in this case I'd swap out the plugs if you happen to have another set (even old ones) to see if symptoms change. Of course the coil packs are also old so that's a good move as well.
     
  3. ghunt81

    ghunt81 New parts on old junk! S197 Team Member

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    Been some time coming (been rainy and busy here and went on vacation for a week), but I pulled and inspected all the plugs, applied nickel anti seize on reinstall (I had used copper before) and installed the new coil packs. Everything seems to be back to normal so one of those things fixed it, at least.
     
  4. Oliver Vigil

    Oliver Vigil Junior Member

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    Ensure the terminals are tight and PCM just may need to relearn throttle position. Let it idle for a bit and drive it around. If the issue persists, I would look at diagnosing the issue then.
     
  5. DieHarder

    DieHarder Member

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    Glad to hear she's back to normal. I put in a new set of coils and Brisk plugs myself. Noticed slight improvement in idling and running great overall. Now, I just make it a habit to check them once a year and replace when needed. Cheap insurance in my book.

    BTW, how's the floor fix holding up? Completed the driver's side on my sons car a while back but will probably have to do the passenger side this winter. Overall, fixes are holding up well.
     
  6. ghunt81

    ghunt81 New parts on old junk! S197 Team Member

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    Seems to be holding up fine, but I still haven't had a chance to figure out how water is still getting into the car. I've been putting it in the garage when there's a chance of rain, but I'll probably have to strip the interior again this winter and see what I can do. Really sucks but now I'm glad I put primer and two coats of paint on that floor. Also the new sound insulation stuff I put in doesn't soak up water like the OEM stuff did so at least there's that.
     
  7. DieHarder

    DieHarder Member

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    Well, according to the TSB there's only 3 places on each side up front where water can get in. I'd recommend stuffing rags or paper towels into each of the holes. Spray water all over the front windshield and then check which one/one's are leaking. It can only come from a couple of locations. At least in my case it doesn't matter if it still leaks a little as I fiber glassed the entire floor (now water proof). Still a pain drying it out however.
     
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