Check the curb weight of the vehicle, and just look at the profile to deduce the aerodynamic drag at higher speeds.
The biggest factor on mileage is driver habits.
The engines are far more efficient than they were in the past, that is why you see bigger V8's making pretty darn close to the same mileage as smaller V6's. The weight and aerodynamics is why you get poor mileage.
18MPG doesn't sound too bad, most V6 Commander owners get about that, less with more in town driving.
A V6 usually gets a MPG or two more then the V8, someone posted they are getting the same with their 4.7L V8, I suspect different driver habits is what erases that slight difference between the two of you.
Originally Posted by allwayz_thinkin0806
I get roughly 21 mpg combined city driving alone i get 18mpg but when i reset it when i get on the e-way i get 27-29 mpg at a steady 80 mph
Wow, best I've done is 25MPG holding a steady 50mph, start and stop measuring once I reached the steady 50mph, doing 80mph drops me to 16mpg or less. I've got the 3.7L also, something has to account for that big of a difference do you have different sized tires?
BTW, 44PSI is the max rec press for the OEM tires, yea, 1PSI over is going to do anything, if you've got different tires, check the sidewall, 35PSI is common for a lot of tires, and being 10PSI over is possible to to cause a problem. Yea, pressure to low is what really causes the problems. Too high of pressure bursting a tire is rare, but HOT roads, on a HOT day in a heavy vehicle with lots of high speed driving, it could happen.