x2^^^^^^^^
You have the 8.1L which will be even harder to squeeze mpgs out of
x2^^^^^^^^Go lightly with your gas pedal, switch ALL the fluids to synthetics(engine,trans and axles) tires aired up, front end alignment, if truck has over 100,000 miles new plugs and wires, clean the throttlebody (I like to take mine off so I can clean both sides with a t/body cleaner and soft toothbrush).