:roflmao::roflmao::roflmao: I have an 07 CCLB completely stock and over a 250 mile 75mph drive thru the central valley of Ca. couldn't pull 14mpg unloaded. When I tow my 27' camper @65mph on a flat highway I get 9.5 grossed out at 13.5K. NO WAY IN HELL 14mpg was achieved pulling 18K.You'd think but honestly towing they are respectable. For example, towing a friends trailer while he was waiting for a tcase (02 8.1L) I got 14mpg loaded. Towing the same load/trailer as well as both trucks are the same cab config he got 11.8mpg.
That is the same drive just on different days about a month apart. Load was a 40ft triple axle load trail trailer with 2 gas pulling trucks on it, grossing ~18k trailer weight with fuel etc in the box of the truck and a cooler.