A while back I posted this amazing 2000 mile road trip MPG report from our Yellowstone vacation https://mirageforum.com/forum/showth...rip-MPG-report where I averaged 51+ MPG. I just returned from a 1400 round trip to Hobbs, New Mexico (about 70 miles south of Carlsbad Caverns). This trip was not as laid back, as I needed to make real time. Average speed limit was 75, and I went 80 most of the way, passing 18-wheelers continuously. On the other trip, I went the speed limit or less, and often tucked in behind large vehicles (not so close as to be considered "drafting", but I'm sure I benefited from their deflection. For this trip, temperatures were in the 50s vs. 80s most of the Yellowstone trip. I just measured my air pressure at 32 psi vs. the 37 for our last trip (ooops!). I did use the cheap 86 octane in NM.
Mesa, AZ to Hobbs, NM: 46 MPG
Hobbs, NM to Mesa, AZ: 44 MPG