it's strange why diesel guys always exaggerate their MPG.Running 70-75 mph towing my 4500+ lbs boat (tall windshield) I average 15-17 mpg. Running 50-ish in construction zones it's 22-24 on level ground. On the highway I'm usually using cruise control but not T/H mode unless it's hilly or a lot of traffic that I need to constantly adjust to. Anything under 65-70 I'm in 5th but above it's in 6th.
But I'm "cheating"...engine is the 2.8.