87 for me as well. Frankly would think 91 would be a waste but it's interesting to see how many of you are seeing / feeling a difference in the 91. I may try a tank to see if there is any measurable difference in the fuel economy.

 

I got a tank from Murphy and Sheetz and boy was that gas CRAP. I lost fuel mileage and my motor started knocking.
I tried some of that BP 97 with Invigorate and it made my mileage go up and ran real good. My next tank will be some of that BP 93. I will try it and see if it makes a difference.
I will never get that trash crap from Murphy or Sheetz again!

 

Woops I meant to say that BP 87!

 

Regular, don't waste your change on Premium.

 

Theoretically, maximum efficiency is achieved immediately before the onset of knock. If your engine is not knocking with 87, then 91 will *hurt* your mileage, not improve it. This assumes, of course, that the computer didn't retard the timing to eliminate the knock using 87.

 

87. I also use 87 when towing my 3500lb trailer with no knock

 

If you have the 6.2 engine in a 2008 or 2009 H2 you are supposed to run premium only.

 

 

As hot as it is in FL I always use premium. In my truck it makes a difference both in performance as well as mpg. I don't think the price difference is worth sacrificing either. Most of the low end fuel here for some reason is crap, so I run premium in everything I own. I don't think the ethanol helps either.

Tim

 

Ditto, premium helps it run cooler particularly while towing.