My 4.3 is still getting better and better since my post above from several years ago. This weekend I just beat my 25 mile record, achieving 33.8mpg on the expressway. I cruised at around 55mph in light traffic, partly in a construction zone. There are several methods to stretch the fuel, all requiring effort by the driver. My wife just drives it with no attempt to hyper-mile, gets 15-16mpg around town. My average over the last 26000mi is 22.2mpg which I'm also very pleased with. I can get the 25mi average up around 30mpg on back country hwys almost every time by cruising 55mph on the flats. I go a little faster down the hills, a little slower up them, using the cruise-control to + - one mph at a time.