I've found a "secret" for near record-setting MPGs.
Gas up in Flagstaff, and head home... This gets me 22+ MPG for the first 150 miles.
Secrets:
1) Flagstaff usually has good "High Altitude" fuels
2) Flagstaff is almost 7000ft while Phoenix is 1250ft (over a mile of vertical descent)
3) I-17 is good quality smooth roadway marked 75MPH except 65 for 2 windy sections
4) If you come home late on Sunday night there is no traffic and little need for A/C until the end (95+ at 1:30AM nearing the Valley)

It's sweet to watch the MDS Light at 78-80MPH for several mile stretches, and 22MPG is my hand-calculated result, even with 4x4 and 3.92 and 34" A/T tires.
Of course, reversing the trip sees only about 15MPG...

 

i'm seeing similar results seigell. road trip last weekend netted 24.7 mpg (hand calc).
4x2
3.55 in the back
stock laramie tires

 

At the end of the month I will take mine in for the update to the computer. Hopefully it will result in the fuel saver light being activated and improve the mds peformance. With a little over 3K on my truck the gas milage is nothing to write home about. I'm only getting around 13 in town (very short trips) and averaging about 15 round trip from Payson to the valley and back. Payson is at 5200'. While its downhill to the Phoenix area, there is enough grades to cut milage.

 

Hey Guys yes i know its a truck got that part. I use 89 octane, 3.92 rear end speed limit in OK is 75 MPH then 70MPH in MO. I just don't understand the mileage when the road we traveled (I-44) is the same both ways. Only difference is direction East vs. West. I'm not bashing my truck I love it just not pleased with MPG. The only thing I can compare it too is my 06 which sucked in the city (13) but highway was 20+ at times. And again I will not drive any other brand. This is my 4th Dodge and have loved them all. I have driven other brands and have had nothing but problems. The worse was a brand new Nissian (Ex-wife) > 100 miles recall on engine. But again don't think i'm bashing the new ram just gas mileage.

 

I'm still hoping to get better milage on mine. I have come to grips with the 13-14 in town due to very short trips. This fall when we take a good road trip will be the time for me to see what it will do on the open road. By then I'll have 4k. I still think the truck is still breaking in.

 

could be the wind

 

I get 15.5-16 city and 20-21 highway.I was told being its a 4X4 its gonna get a couple miles less per gallon.The 3.92 gears don't help on highway driving either.I'm still more than satisfied with my MPG,for a hemi,it does pretty good IMHO...............Kevin.

 

I just got back from a 460 mile trip.

I got 21.3 MPG there, and 19.9 MPG on the way back. The routes were a little different, the way back had a few more hills, and I also hit some traffic on the way back. But while I was moving, I average around 75MPH.

The MPG figures are hand calculations. EVIC showed about 0.5MPG higher.