awful was my last truck. It was an 85 chevy 4x4 dually with a stretched frame, 12' flatbed, 8" lift on 37" hummer tires. Had a very worn out 454 on 4 speed stick. Got a flat 3 mpg, even worse if I put my foot in it. I could go through 80 bucks of gas a day staying within 20 miles of my house...