I would ckeck with the dealer you might have a problem with your overhead display.Mine started on my first trip.

 

I have the 5.7L Hemi, with just around 900 miles, and the overhead shows about 10.5 mpg. Almost entirely city driving. Hopefully it will increase as the engine is broken in?

 

It should mine has 7200 miles on it now and i get about 12 mpg in town. How`s your highway? mine is about 18 mpg.

 

We will be taking a 3,000 mile trip for Thanksgiving so maybe we can provide some highway experiences upon return. Driving from Scottsdale, AZ to Spearfish and Rapid City, SD. I will try to get fuel mileages in both directions so the mountains don't have such a huge effect.

We have just over 4,900 miles on the car today, before we leave Saturday morning.

 

I think i would check the oldway. Then compare.

 

Added a TrueFlow intake system. Getting 22+MPG at 70mph highway. Not too bad

 

We just got home from our trip of 3022 miles from Scottsdale, AZ to Spearfish/Rapid City, SD. Lots of wind and certainly lots of elevation changes as we saw over 7,000 ft. elevation about 10 or 12 times this trip. Gas mileage by the old fashioned method for the total trip was 18.1 mpg. The computed mileage per tank in general was about 1.0 mpg higher than actual.

Best tank of gas was 20.1 mpg as we dropped down the mountain coming home. Worst tank was 15.5 as we climbed the mountains in New Mexico with very heavy head winds.

5.5" of snow in Spearfish with temps as low as 6*.

Car was great, no issues of any kind except for the sudden adjustment of the drivers seat in an unpredictable, unexpected timeframe. Seat moves up and back to same location with my memory settings, with Susan's memory settings it moves forward only and must be readjusted manually. We cannot detect anything that is consistent with the movements, but it is very disconcerting and dangerous. In the 3022 miles we drove the seat moved probably 30+ times.

 

I assume most of these figures are with the 3.55 rear.

I just ordered my 2008 and the towing package forces you into a 3.92. Anyone have mileage specs on a 5.7 with 3.92??

 

All of these mileage figures are with the 3.92 rear axle. That was the option installed on our car.

 

They still have not figured out your seat problem? You hvae had that for a while, must be driving you absolutely nuts. Although, when you are driving that far, it can be used to help keep you awake, LOL.