buickanddeere
Super Member
My 1500 Silverado with a 5.3 only gets about 12 mpg around town. Pulling a trailer that weighs about 2,500 pounds drops it to about 10. It gets about 16 mpg on the highway, The F-350 with a 5.4 does about the same and a little better when towing due to the lower gear ratio. A family member has a 3500 Dmax. He gets about 19 mpg on the highway and about 11 mpg pulling his 14,000 pound 5th wheel. He used to have a 7.3 F-250 that got about 25 mpg unloaded and 11 mpg towing the 5th wheel. My gasser f-350 gets about 7 mpg pulling that load and can't run with the D-max.
5.3 port injected or 5.3 Direct Injected ? The early 5.3 and late 5.3are almost as different as a gas engine is from a Diesel engine .