Yes, I know there is hundreds of threads about this. I'm just gonna do some ranting. My Jeep is averaging 14.3 mpg city and I drive like a grandma. I mean like I'm the lightest of the feather foots. Enough of that ranting. Anyways, I was talking to my friend's dad who has a Hummer. His dad drives an H2 with: 10
in. lift, 37 in tires, 5.2 L V8 and so many other features that are mind boggling. His 10,000 pound behemoth is averaging 13 MPG. Talk about about discouraging that my 3,000 pound V6 is only getting 1 more MPG... But whatever, I guess it comes with the territory!

 

I would like to point out that his hummer is now no longer in production. I am getting 14.0 to 15.5. I drive sane and use 93 octane when available (around here in east Texas u get either 92 or 93 as the max octane) with superchips tune for 93.

My gas milage was not really impacted by the octane boost, it just has a little more power so it dont downshift as much, especially when the doors and top are off, mpg goes down- i leave the top and doors off for 8 months out of year and drive my bmw during work and rain-y-fied weather

I have an 09 4dr rubi with auto. 4.10 gears and stock tires. I have tracked my milage since i bought the jeep new with175 miles on the clock. It now has 34000. I use the gas cubby app for iphone, it displays actually mpg at each fillup and also avg mpg over entire history of vehicle. and i have no faith in the jeeps mpg display at all, way off.