Look out for bad gas. This weekend i filled up 1/2 way w/93 octane, and had spark knock out of boost. as soon as i heard it, i went to the station where the fuel was purchased and the owner stated it WAS 93. i got a sample and went to a buddy with a knock engine where the rating was stated 85 octane. i got (2) bottles of 104+ AND topped off with 93 Chevron and the knock went away, BUT the CEL came on with p0300 Random Misfire Detected. Upon further diagnosis i found cylinder 7 misfiring at idle only. Compression Test was 90 psi on 7. All others = 190. Luckily the truck has 20K on it and is still under warranty, BUT i gotta put it back to stock for the new motor. SO Look out for shitty gas! ill keep the forum posted.

 

Wow man, that really sucks. Taking that blower off and putting everything back to stock is going to be a PITA. keep us posted.

 

Ouch!

 

YIKES!!! Maybe you should detune it a little in case that happens in the future. It sounds like you have a really aggressive tune in there. What do your high and low octane tables look like? Are they identical?

 

16 on low octane, 21 on high...not tOO aggressive. the gas caused it ;(

 

I wonder if it made it all the way out here?
https://www.performancetrucks.net/fo...d.php?t=396426

 

I have heard that some dealerships will not cover bad gas. They say it is your fault and they will not cover the damage. So just don't mention you got a batch of bad gas..

 

stoich, Check compression, mine had a misfire on #7 and #2, its obviously ringlands. the 4.8, 5.3, AND 6.0 are supposedly notorious for failure with boost conditions, and lean/low octane mix. i was running 26 degrees advance under boost (8 lbs). the intake will be back on by lunch, and EVERYTHING changed over. will miss the truck for a few weeks

 

I hate to tell you this but your dealer is not going to cover your bad gas. They will probably tell you to pay for it and get your money back from the gas station...

 

I did a cylinder balance test, with good results. I think my pistons are fine, just something is flipped out with the pcm. I can't completely rule out the gas, but it is interesting that you had a similar experience at the same time.