[Joe M 2012 2SS]

Ok I've had may 2012 2SS L99 for a little over 2 months now.
I do primarily city driving @ 25-45 mph. Initially the car stayed around 11 mpg using Hess 93 octane.

I did a little research and saw where GM recommends using top tier gasoline.

So I ran out the Hess and filled up with Mobil, did the fuse pull, and increased to 14.5.

I recently used a tank of BP 93, which is also supposed to be top tier, but went back to 11mpg.

So I ran the BP out, put Mobil back in, did the fuse pull again, and I'm currently getting 14.6.

Evidently all top tier gas is not the same. There is a Texaco station close to where I live that sells non-ethanol 93 that I haven't tried yet.

Anyone noticed mpg gains from non-ethanol?