Yeah, I totally agree, there's much more to milage. Your wife's 10 mpg is what I would expect from a lead foot driver. And you getting up to 18 doesn't seem impossible under ideal conditions. But 22 MPG??
Some other factors impacting the mileage when I got my best of 19.6 mpg:
☆ As you mentioned, driver. I was driving like there was an egg between my foot and the gas pedal. And with hills and valleys, I didn't try to maintain a constant speed; I let the car speed up going down and slow down going up (i.e. avoid moving the throttle.)
☆ Also as you mentioned, tire pressure. I was running 36 psi in the 215 (f) and 235 (r) tires.
☆ Fluid type and viscosity: I have synthetic 10w-30 in the engine ATF+4 in the transmission, and synthetic 75w-90 in the rear.
☆ Aerodynamics - a 70 Dart has terrible aero, with the flat grill inset into the nose, drip rails, concave rear window, etc. But can it be any worse than a 2000 Durango?
☆ And one of the most important things: WEIGHT. My Dart is about 3150 lbs unloaded, your Durango 4600 lbs. With your truck being loaded up it was probably a solid 1800 lbs more than my car!
Did the 22 mpg calculation come from the Durango's trip computer?
