Originally Posted by fcbubba
I went on the first long (for me) trip since I purchased the truck. I have about 4 thousand on the clock and been averaging between 18 to 18.9 driving around town and speeds up to 60. I usually drove between 70 and 80 on this trip and was only getting around high 17's or sometimes high 16's. I have an 8 speed tranny and 3:21 gears. Should I be concerned or is it because of the higher speeds? Thanks
If you, like me, have one of the first Hemi 8 speeds, you may need to get the new PCM flash from your dealer. I was feeling like my mileage just wasn't quite what it should be too. I have not 'proven' it but I think I picked up 1-2 mpg's afterwards and the transmission just acts better. At least, my average mileage on the computer has gone up about 4 tenths over the last week or so.
When my truck was stock, it would run in the 17-19 mpg range on the highway at 75-80 mph. At 65 mph it would get 20+.
Now it runs 15.5 - 17.5 with the lift and 33" AT tires on the highway.