08 lmm duramax, 2wd ccsb winter mpg hand calc avg 15.6 around town. i usually avg 20 not towing on hiway, wife has coaxed 24 out of it, but not very often. towing i recall last yr was about about 11 with a 5er i have no idea what it weighs. we travel "light" tho. we only have 35000 on odometer, so im hoping it will get a little better when it gets broken in.