H3 MPG < H2 MPG

[H3.007]

I have the stock 33s, t-bar turns levelled to rear, a brush guard, rear bumper bar, factory off road lights, and vent shades. My mileage had been in the estimated range and still is, for the most part, on highway trips. However, after the 6,000 mile mark, I have noted a definite decrease in city mileage. I am not quite sure why although I had been driving it quite aggressively in expressway conditions, frequently kicking high rpms. On my current tank, I am going to try to stay out of "afterburn" and see what the mileage is as I suspect of you drive it like a granny, you'll get the best MPG, but if you drive it like Ricky Bobby.... well, you get the point.

Has anyone ever conducted a test on gasoline grades and what gets the best mileage in the H3 under normal driving conditions?