I have a 2021 Laramie Sport with 5.7 e BS and 3.92. I continually average 17mpg per dashboard. Lot's of hwy miles SW Louisiana to Tampa 8 times plus DFW, ATL, HOU, etc. got 62K on it.
Just for fun, I slowed down to 60 for 20 miles (in a 60mph zone), got 28mpg indicated. Drove 70mph in a...