I am jealous of pretty much all of y'all.
I've got 5000 miles on my truck now. 3.92, Hemi w/eTorque, stock 22s with stock tires (meticulously maintained at stock spec pressures - 36 psi cold), air suspension (which means it lowers to Aero mode on the highway). My overall average is a bit over 14 MPG right now. The best I've gotten on a tank is 17.9. All in all, probably 1 - 2 MPG better than my 4th Gen ('09).
I track every fill-up with Fuelly and I note down what the the tripmeter says the fuel economy was before I reset it, so I can compare the lie-o-meter to hand calculating. Once, the truck computer mileage was spot-on with the Fuelly-calculated mileage. Most of the time it's off and sometimes it's off by as much as 1.4 MPG.
So, y'all that are going off just what the truck says your mileage is might be kidding yourselves.
Regardless, I'm not surprised my mileage is low compared to most folks. I pretty much only have 2 speeds. I'm either driving somewhere within a mile or maybe 2 miles from my house. All, in town. So, it's all constant speeding up and slowing down. Or, I'm getting on the Interstate and setting the Adaptive Cruise Control to 80 MPH. Traffic around here, even on the Interstate, sucks. So, even when I'm on the Interstate there ends up being a fair bit of slowing down and speeding up. Between 3.92 gears, going 80 (versus, say 70), and all the speeding up and slowing down, even highway driving is going to give me low mileage.
I drove from here to Pittsburgh and back last weekend. I got gas at a travel plaza on the PA turnpike. 50 miles later, my tripmeter fuel econ was showing as 21.1 MPG. I guess my truck is CAPABLE of getting okay mileage. If I can find some road that is not too crowded and the speed limit is 55 and not 70....
I do think that, when you are saying how many miles you've got, what gears you have, etc., you should also give some indication of what your driving is like. I.e. are your highway miles mostly at 65? 70? 80? On congested highways or pretty uncrowded ones?
I'm just glad I have a 33 gallon tank. With this mileage, if I had a 26 or smaller, the more frequent stops would chap my a$$. Especially on road trips. I go home to Tallahassee a few times a year. I think the 33 will let me drive it with only 1 stop, but a 26 would require 2. I'll find out at Thanksgiving...
