Hi guys
I've got a 2004 Silverado 5.3L V8 with 175,000 miles that has been having spark knock intermittently since I got the vehicle in 2007 with 65,000 miles. I always use 87 octane fuel
Only in the past 3-4 years have I been actively searching for a resolution but I found that with this cooled down weather here in Houston Texas the spark knock has disappeared and I'm not sure what's the reason
I have an ODBII transmitter with the torque app on my phone tracking the knock retard and timing and the odd thing is that when I actually hear evidence of spark knock occurring, most always under medium to heavy load in gear and at the upper range of RPMs; 3,000-6,000 RPM, no spark knock count is increased nor is the engine computer retarding the timing to compensate
Now all the sudden with the weather cooling off I noticed, again, under the same load conditions mentioned above, the engine started to spark knock only slightly then stopped and all subsequent times I've loaded the engine, when chilly out, the spark knock has disappeared.
Could the heat or hot days be the actual cause of the spark knock? Or does this point to an issue with the gasoline not dealing with high temperatures very well? Perhaps both or something else entirely?
I have done nothing as far as repairs or maintenance to warrant any change in behavior yet now on chilly evenings if I actively attempt to forcefully make the engine spark knock it is not occurring even under the heaviest of loads I'm comfortable putting the engine up to which is pretty high but not stupidly or dangerously high (not maxing it out or anything)
Hoping some of the intelligent and experienced minds on this board can shed some knowledge on this matter so I can better safeguard myself from damaging the engine
Thanks for looking
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