Constant misfire and oil on plug.

Discussion in 'Generation 4 - Maintenance & Troubleshooting' started by CCXVI, Oct 13, 2019.

  1. CCXVI

    CCXVI SHO Member Supporting Member

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    On the way home the car lost power and barely made it up the driveway. Got misfire codes, including cylinder 1. Swapped coils and it stayed, pulled plug and it looked good but has oil on it. No strong gas smell, but it could still be the injector. Are plug seals a common failure, and could it leak enough to cause a misfire?
     
  2. luigisho

    luigisho SHO Member

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    Did you clean the area and put a new plug in? Yes oil can foul spark plugs if that is the question. Not to be one to just throw parts at things, but a repacement plug is cheap and easy to take care of. If that cures the misfire then replace seals and you should be good to go.
     
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  3. CCXVI

    CCXVI SHO Member Supporting Member

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    Yeah, cleaned the plug and it still acted up. Still need to swap the plug with a good one just in case, but this is the 12 hour nights weekend so its waiting until a day off
     
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  4. luigisho

    luigisho SHO Member

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    You are sure the misfire didn't move from one cylinder to another? Hard to be sure without a code for which cylinder has misfire
     
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  5. CCXVI

    CCXVI SHO Member Supporting Member

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    It gives you a code for which cylinder is misfiring. It was still cylinder 1.
     
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  6. SHOdded

    SHOdded SHO Member Supporting Member

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    Valve cover gaskets commonly fail on Bank 1 on Gen 5 SHOs. Usually cylinder 3 but hey LOL.
     
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  7. CCXVI

    CCXVI SHO Member Supporting Member

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    Alright, I'm gonna pull a few more plugs and take a look at them and then see if moving that plug moves the issue.
     
  8. krewat

    krewat SHO Member

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    Uh, oil on the insulator side or the spark-side of the plug? ;)
     
  9. CCXVI

    CCXVI SHO Member Supporting Member

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    Spark side. Insulator side was clean.
     
  10. luigisho

    luigisho SHO Member

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    Not 100% sure about the newer motors but usually leaky vc/ spark tube gaskets leak up top. Is this different on this model?
     
  11. krewat

    krewat SHO Member

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    No valve cover leak in the world is going to put oil on the combustion side of the plug unless it was on top and got on it when you pulled the plug. But then, the insulator side of the plug would be wet too.

    You either have a bad turbo seal, or your PCV is sucking oil. Hopefully, the latter ;)
     
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  12. SHOdded

    SHOdded SHO Member Supporting Member

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    I was assuming oil on the plug threads, not on the electrode itself. If there is oil on the threads, the valve cover gasket is the likely culprit.
     
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