I use Shell fuel but it’s Top Tier fuel in my area, and I know that it’s not Lew’s favorite but I’ve never read why he feels that way. I’ve used Lake Speed Jr.’s research and videos for a lot of the things that I don’t fully understand. It’s going to be a big problem if you don’t get it addressed, detonation will ruin a engine relatively quickly. If Lew happens to see this please chime in and educate me.

 

Yeah, all Shell's are "top-tier"... doesn't mean anything... they pay to be on that list...

Make sure you are using GOOD 89 octane gas, it makes a difference!!... Mobil, Exxon, Sunoco, Amoco, BP, Chevron - are the best brands to use...

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

If you can't use any other brand because of a company card, then get 91 octane man...

Yeah, shell is crap gas.. found that out myself many many years ago with my own car. I used to use Shell gas myself years ago... then when I got into tuning and data logging (16+ years ago), I started data logging my car, and noticed I had a TON of knock retard throughout the whole data log... even with just normal steady, easy driving/cruising around town... and worse when I got on it... I was like WTH??? So, made adjustments to my tune, didn't help... so then I ran that gas out and switched to Mobil 93 octane instead, and ran that out.. filled up with Mobil 93 again.. and VOILA!!! All of that knock retard was gone... Virtually all of my knock retard issues were gone!! Shell gas was the problem! It's shit gas, the additives they use are the problem... And over the past 16+ years of doing this, I can usually tell when someone is using shell gas, because when I look at their data log, I will see a ton of knock retard throughout the entire data log...

So yeah, definitely don't want to use Shell at all, or any of the others I mentioned not to use... You want to use GOOD gas - mobil, exxon, sunoco, amoco, bp, chevron....

 

Yeah, all Shell's are "top-tier"... doesn't mean anything... they pay to be on that list...

Make sure you are using GOOD 89 octane gas, it makes a difference!!... Mobil, Exxon, Sunoco, Amoco, BP, Chevron - are the best brands to use...

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

If you can't use any other brand because of a company card, then get 91 octane man...

Yeah, shell is crap gas.. found that out myself many many years ago with my own car. I used to use Shell gas myself years ago... then when I got into tuning and data logging (16+ years ago), I started data logging my car, and noticed I had a TON of knock retard throughout the whole data log... even with just normal steady, easy driving/cruising around town... and worse when I got on it... I was like WTH??? So, made adjustments to my tune, didn't help... so then I ran that gas out and switched to Mobil 93 octane instead, and ran that out.. filled up with Mobil 93 again.. and VOILA!!! All of that knock retard was gone... Virtually all of my knock retard issues were gone!! Shell gas was the problem! It's shit gas, the additives they use are the problem... And over the past 16+ years of doing this, I can usually tell when someone is using shell gas, because when I look at their data log, I will see a ton of knock retard throughout the entire data log...

So yeah, definitely don't want to use Shell at all, or any of the others I mentioned not to use... You want to use GOOD gas - mobil, exxon, sunoco, amoco, bp, chevron....

It could very well be the additives themselves in Shell that is having the effect. Like everything blended info the fuel will have an ignition point and not all the same. So all those "cleaning" agents may actually be lowering the octane rating. In my area Exxon/Shell is scarce, no Mobil BP Chevron Amoco but we sure do have the Valero and a sprinkling of Sunoco. Never had any issues with Valero gas myself and it runs good in the Caddy as the wife prefers to run it over e85 because the tank last longer nor does she care if the car is making ~600 vs 650ish.
During a hurricane I ran some Sam's gas because all the other stations were full or empty. I could feel the difference in my truck like someone had flipped a switch depressing my engine.

 

Thanks Lew! It's funny how it just started happening a few months ago, maybe they added more shit to the formula. I'll run 2 tanks of the 93 octane and see if it makes a difference. If I don't get yelled at by the office manager on the cost I might be ok.

 

Carbon buildup can cause engine pinging {increase compression) and with that many miles it would not be uncommon occurrence.

Whats the tailpipe look like? Black?