I traded a 2011 GMC Sierra 5.3L V8 WITHOUT Active Fuel Management (Cylinder Deactivation), 4WD, Lifted w/ 33s, and from 0 miles to 22,000 miles, it never gave me this low of mileage, with a larger motor, larger tires, a lift, and more weight. It's a hard cup of Kool-Aid to drink to believe that...