Regular or Premium gas?
 

What does everyone use in their H2?
Does anyone notice any difference in mileage or performance between the octane?

I only use 87 octane (regular) or 89 when that's all that's available. I've never tried premium because regular works just fine. I doubt a person would be able to measure the difference in MPG, unless MAYBE you were on a controlled track.

87 for me. It runs perfect on that. I put 91 in my bike and the wifes CTS.

91 Chevron Super for our H2. I can feel the performance difference if I go with the cheaper 87.

I use 87 for normal driving. when I pull my trailer or go to the sand dunes I use 91.

use 87 every new engine with a knock sensor can run on 87 without any harm computer senses any ping or detionation and retards timing as necessary. Dont be fooled buy 91 only stickers. You will loose some performance but there is no harmful effect

I use 87 only, but I have programmed my computer for 87 with performance. Runs great!!!! 12 mpg city/14 mpg highway.

I use 87, but I just added some octane boost, and wow....I'm gettting great mileage with the boost!

87... hope you did not get your H2 for its great gas mileage... :)

87............