Originally Posted By: TrevorS
A 20% mpg difference is hard to believe.
In my experience, using the same Mohawk fuel in my old Audi, I had reduced fuel economy. I wouldn't call it 20%, but I would definitely get fewer miles out of every tank of Mohawk than when I used Esso pure gas 91, and that was with some repeatable driving. Of course, whether or not it was actually statistically significant or if I missed other factors is another matter. Closer to 10% would be my guess, but that's getting into the background noise, really.
In any event, I haven't used it often enough in my G (they clobbered the Mohawk CAA rewards program) as I did in my Audi to see if it makes as much of an apparent difference in the G as it seemed to in the Audi.
Maybe I'll run a few tanks and see if I can notice anything. As for your suggestions about the higher octane or a different quality gas, that's certainly possible, too. Not that it matters much, but it's not a Top Tier station up here.
Perhaps Mohawk's 94 octane degrades quickly. Clevy has noticed other problems with it before, and I got one terrible tank in the Audi. It was to the point the car would barely idle. When I had my Lightning, though, I never had an issue nor had any noticeable difference in fuel economy.