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  1. #1

    Default Detonation. . .why now?

    I have a 2007 Silverado Crew Cab, 2WD 5.3L with 45000 miles. Since new, it has not had an issue running 87 octane gas, but lately it has been pinging under moderate - full throttle. I tried higher octane gas, and though it pings less, it is still there. This truck has never worked hard a day in its life. I have thought about replacing the spark plugs, but I have had other vehicles run much further before needing replacement and doubt that this could be the problem. Could I have a bad knock sensor? If so, would the check engine light come on? I do not wish to continue spending the extra money on 89+ octane gas.

  2. #2
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    Default

    It sounds like you have the typical 5.3L carbon build up problem. i would try a really good seafoam treatment. and then go from there because the 5.3L had a habit of building up carbon in the combustion area that would cause detonation... keep us posted as well.
    Mike

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  3. #3

    Default

    Yep a little bit of carbon build-up goes a long way.
    Try a SeaFoam treatment as previously recommended.

  4. #4
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    Good idea on the Seafoam, but I would also clean the MAF and throttle body. I had the same issue with my Suburban along with an occasional check engine light when under hard acceleration. Cleaned both and it is running like a dream.

    Good luck!

    Joe
    2003 Suburban
    1968 Camaro 454

  5. #5

    Default

    Yep, Seafoam, clean throttlebody and MAF.
    :cool:

    2005 Chevy Silverado Z71 Crew Cab
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  6. #6

    Default

    All good advice here...

    Don't forget to do a fuel pressure test. Low fuel pressure will cause detonation, which causes damaged rod bearings, which causes...
    When you hear hoofbeats, look for horses not zebras.

  7. #7

    Default

    Sounds like good advice to mem does the truck diesel when you shut it down?

  8. #8

    Default

    It's not going to diesel, the fuel pump and injectors are off.

  9. #9

    Default

    That's a good point.

  10. #10

    Default

    Well, after adding a can of Seafoam during my last fill up, the detonation is much less than it was. I will try another can with the next fill up and let you know if it finally goes away. Thanks for all of the ideas.

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