Might be the built trans, tunes, and that right foot enjoying it all, hah
Definitely not the right foot... I drive too easy. Could be the built trans or tunes or both I guess. Seems like I was squeezing about 1-1.5 MPG better before the trans build. Yours is a mix of city and highway driving though, right? Mine's all stop and go city traffic so I know that kills MPG.
2006 Silverado 2500HD 4x4 crew cab (black), 20" chrome Moto Metal 962 wheels wrapped with 32x11 Toyo Mud Terrains, 2" wheel spacers, Bilstein 5100 series shocks, Banks Ram-Air Intake, custom straight pipe exhaust w/5" tip, EGR Delete, FASS 150 lift pump, PPEI dsp5 tuned by Kory, Suncoast Gmax 6 w/1056 converter, Edge Insight moniter, 8k HIDs in head/foglights, Limo tint, 7" Pioneer Double-din, (2) Boss Phantom 12s in custom box, more coming soon...