Used 2003 GMC Sierra 3500 Extended Cab Consumer Reviews
Truck looks great! Fuel mileage (non towing) is not bad for a ton dually at 13 mpg. Towing is another story. Six (6) miles per gallon is the average for this 6.0L engine. Tow mileage is terrible and the truck is at its maximum performance on the interstate at 70mph. It absolutely has no power left.