2018 Navigator 6mpg when towing 8k lb camper Ecoboost

My 2011 Yukon with the 6.2 doesn’t get that good of MPG when I’m towing my relatively aerodynamic boat. I’m surprised yours would have done that well with a TT.

As others have said, that speed will kill MPG. If you want it to improve, slow down.

As to those concerned about his tires, there are now a number of ST that are speed rated above that 65 MPH.