Diablosport Forums

Had posted previously and received some help them nothing. So thought I would try again.
2007 GMC Sierra 5.3 gas new body style. U7194 with 9r31 I installed the 87 tune and I was getting spark detonation in the lower RPM.

I am using Shell gas and I cleaned the MAF with MAF cleaner. My ltft was at 10.16 and 10.94. I set my injector slope to -9.

After 350 miles I did a data log this is what I got.

Ltft  are +0.78 and +0.78

Intake air temperature was at 64.5°

I did notice a big decrease in the spark knock but I still have it. If I accelerate just as speeding up another 5mph it knocks.  Any help would be appreciated.

A-HAA!!! Make sure you are using GOOD gas, it makes a difference... mobil, exxon, sunoco, amoco, bp, chevron are best brands to use, with mobil and exxon being the best..

NEVER use Shell, walmart/sams club/bj's, mom-n-pop, or no-name brands, as it's crap gas/additives that tends to cause a lot of knock retard and less performance/mpg...

We have a Mobil station here I will fill up with it this week.

Well 2 tanks of "good" Mobil gas ran and still spark detonation. Guess I'll go back to the stock tune and maybe adjust the injector slope. Not sure what the 87 tune adjust but it's not for my truck. No issue with the detonation when it was a stock tune. The milage booster tune would detonate worse then the 87.