I'm figuring it out when I fill up using miles traveled/gallons put in. Can't go wrong that way. But the overhead is usually somewhat close.

 

Mega cab + 2500 frame + 345hp = SLUUURRRRRP

 

well, if you do add some extra bolt ons to your mega cab and do pull off 2 more miles to the gallon it would be something like a 15% percent increase in gas mileage.... id be pretty happy with that even if i wanted to get to 16

 

Nope, no MDS in a Mega, whether it be a 1500 or 2500.

as far as the mileage while pulling, the Hemi seems to not mind pulling weight until it gets up over 4000 lbs. When I had my bass boat, which was prolly in the 2200 lbs range with gear, I could pull it on the highway and get damn near the same mileage as with the truck alone. Only stop and go driving was really effected...

 

i get 18 mpg....and push 38's lol

 

2007 Megacab 1500 4X2 w/ 3.73 - stock
I have 10K miles on it and get 12.5 mpgs mixed, 14 mpg strictly highway, and 9 mpg pulling a 6500 lb - 30 ft travel trailer in flat terrain

Great truck. I am getting what I expected so I don't have a problem with it. I doubt any other 2500 gasser out there gets much better.

 

I decided to buy a diablosport programmer since that seems to be the best bang for the buck as far as better mileage. Any other tips? I was going to change plugs, but keep reading that they are good until 60k miles not 30k like dodge states. Also, will just a K & N filter improve mileage or do you need the whole CAI kit? I'm eventually going to put on better exhaust, but one thing at a time for now. But like everyone else has said, it's a truck and to serve it's purpose as a truck you can't expect great mileage. Which I'm not, but I want better than what I'm getting right now.