my highyway and towing mileage were acalulated on interstate trips 500 miles or more with cruise control on summer blend,,winter blend will knock milege down about 1 1/2 mpg empty,,never towed in the winter

 

location: denver (5400 ft.)
driving 85% highway (65 - 85 mph)
driving style: not to hard and not too soft (get in it hard every now and then)
gears: 3.73's
48RE auto

Mileage:
in town 17
highway:19... all hand calc'd because the overhead computer is always +2 mpg more than hand calcualted. (generally I get 520 miles before the "get fuel" light comes on (approx 1/8 tank)

35 gallon tank.

 

Just finished a 2500 mile road trip with a variety of driving conditions and averaged 20.4 hand calculated. Of course driving habits make a difference. I am also convinced there is variation in similar vehicles.