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Discussion Starter · #1 ·
My truck, a '00 GMC w/a 5.3 w 100k miles, has the annoying start-up piston slap. However, at about 2000-2100 rpm, there is a little knock, depending on the throttle position. Is this related, or is it something else? Michael
 

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Paint it Black
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i have the annoying as hell piston slap as well in my 2001 5.3 and it started around 98K. At about 104K, i started getting a little bit of pinging, and just switched to higher octane gas, and it went away completely. i still get the slap, but no more pinging, so i would venture to say that they are not related, but try a higher octane.
 

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HOT AIR BALLOON OWNER
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Could have hot spots in the chambers too. Run some SeaFoam or GM Top End Cleaner to burn that crap out of there.
 

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Discussion Starter · #4 ·
Thanks. I'll give that a try. I have been considering Seafoam, but haven't found any local.
 
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