These companies have to pay something for that rating.
"Ain't no free lunches" anymore.
Additive manufacturers pay for the testing, which costs an estimated $25,000 to $30,000, while gasoline companies pay an annual fee based on the number of stations it operates to participate in the program.
Maybe since Sunoco owns Sunoco unlike Shell, Mobile and others they didn't want to pay and decided their fuel speaks for itself.
Only my conjecture.
Makes sense since you don't really hear too much about companies claiming they are a " Top Tier " gas company in their commercials.Honestly, I had never heard of this before your post.
Mike, thanks for the information and it makes perfect sense. I have noticed especially over the last 5 or 6 years the effects on small motor items, two and four stroke motors, on everything from lawn mowers, snow blowers, weed eaters, etc. various fuel system components such as but not limited to fuel lines and o-rings deteriorating, along with rust and carbon build up issues. This equates directly to what is going on in the fuel systems in our vehicles.