Don't know why mine is so different. I towed my 6500lb TT about 150 miles and got 11-12 mpg. I didn't smell anything from the trailer's brakes or anything so I don't think they were dragging. My mpg is right as expected when I am not pulling. Welcome to my world.
I'm with you I get shit mileage. Maybe it's Minnesota roads. Maybe 10-12 towing a 16' enclosed tandem axle trailer. Loaded or empty. Pickup box trailer with a Topper, ~12MPG
Hell I'm driving completely empty on I-29 right now; cruise at 76 in 8th gear with a 10-14MPH headwind and I can't break 16
And this is with a winter front, +10°F, 3.55's, 4x4, and air suspension.
I'm with Shawn with the Progressive MPG drop. I drive 63MPH (speed to hit Aero mode) pretty religiously on our state highways and I get all of 22MPG. 25 on a good day.
My only option is to drive 55 down wind if I dream to see 28MPG as of late.
But it's pretty consistent I get ~22-23 going 63. Jump on the freeway at 75 and get 17-18
Anyone here to tell me that something just isn't right with my truck lately?