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Discussion Starter #1
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.
 

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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.
 

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

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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!
 

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Yep, Seafoam, clean throttlebody and MAF.
 

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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...
 

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

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Discussion Starter #10
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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Nothing wrong with Seafoam in the tank, but if you want to utilize it to the best of it's abilities you really need to do an intake cleaning with it. I recently tried the new style can with the throttle-body adapter, works well but I kind of preferred the old method of pulling the brake booster vacuum line off and pouring in that way. However, using that throttle body adapter probably does a better job of evenly distributing the solution throughout the cylinders.
 

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Discussion Starter #12
After two consecutive tankfulls w/Seafoam, the pinging has disappeared and I can once again run 87 octane fuel. Thanks for the advice ! ! !
 

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Discussion Starter #13
Well, the pinging is back. Truck has 56,000 miles and now spends more time on the highway than in town. I will begin another Seafoam treatment starting with the throttle body cleaning, but will this be a re-occuring issue that will need constant attention, or is there a perminent fix the dealer can perform? I purchased the extended warranty when new and since I have moved back to Texas I can take it to the dealer it was purchased from.
 
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