i get anywhere between 16-17.5mpg in the summer and as low as 13mpg in the winter, depending on driving style with a 5spd....and again, shifting at 1000rpm or 2000rpm isn't gonna save you ANY gas, you can shift at as low an RPM as you want, but if you shift at a low RPM and mash on the gas, theres not gonna be any power there to get the truck going, your only boggin the engine, so your only wasting gas, i shift at whatever RPM i feel necessary during different driving styles, but on the highway i keep it below 3000rpm, usually around 2700rpm