message to OP- fuel economy is not the best with the hemi for sure.
IMO they should be ashamed of using the same EPA fuel ratings for all the trims with same engine.(rebel 4x4 same as big horn 2wd?). the 3.92 does not get 22mpg highway (70mph) unless my truck is defective.. this is my second one Ram 1500 hemi. last was a 14' on 35"s.
Clearly the weather, suspension/tire mods, traffic conditions, wind, driving habits and hills all skew the MPG numbers in identical trucks and ratios. I've noticed my best MPG over this last year is in 65-80 degree weather (some of our spring and fall seasons). In "florida winter" (40-60 degree mornings) i noticed clearly lower mpg on same route. maybe 1-3MPG lost (longer warmup time and short drives) . the florida summer I blast the AC and e-torque is turned off for max a/c, so no stop light fuel saving.
If we used the "Current MPG" reading while using cruise control at 5mph increments on the flattest road you can find AFTER the oil/trans temp are warmed up we could compare apples to apples/trims to trims/gassers to eco's! (make sure your speedometer is accurate or your #'s might be off!!)
i'd have to redo this test myself for 99% accuracy but if i recall correctly 35mph- around 35mpg 65mph-24-26mpg 70mph-18-19mpg on a big horn crew cab 4x4 - 5.7 hemi e-torque with 3.92 gears and 23 gallon tank empty on nearly all flat roads.
I get my best fuel economy at around 40mph its usually at around 37MPG on the current MPG readout!
grab pen and paper. lay out 25,30,35,40,45,50,55,60,65,70mph or w/e and record your numbers and post it.
As far as tank to tank MPG I managed 15.9mpg last week with hand calculation and a slight lead foot (truck read 16.3) with all city and backroads and some tri-hull pontoon towing on weekends. 6k miles on truck now.
(for more precise #'s drive in both directions and average the 2, this should negate the wind factor, add the conditions and outside temperatures to compare to others )