Realistic 6.7, 6-spd Auto, 4x4 MILEAGE???
 

I am getting about 15mpg in the city and 19 on the highway, I got bout 800 miles on the truck is this going to get better as it breaks in????

Sounds about right to me... They should get better mileage as they break in, but yours is already average or above average...

Some people on this site would kill for those numbers from their 6.7. That's pretty close to what I'm getting though (actually you're doing slightly better than me).

Well not mine 9 towing, 11.5-12.3 city 14.7 hwy, I put a mp-8 to see if there would be a increase in mileage and none so far.....So count your blessing with those numbers.

floridagc

Why is it the 4x4's get such bad mileage???

A buddy of mine has a 2wd 6.7 and a 6spd manual and he is getting 17 in the city and 21 on the highway...

I'm around 15 City but haven't been on a trip without towing ,hope I get 19 like you but I doubt it. Towing 11m lbs. I'm at 10.5.
Mine has 12m on it now.

My Dad is getting 16mpg highway with his MC dually 4x4/6.7/6spd auto. Can't really complain for such a large truck. Towing is around 11-12mpg.

MikeyB

I would say it's due to parasitic drag throughout the added driveline mechanisms and the added weight of them. At least that's been the historic reason.

Your numbers are excellent . . . anyone seeing improvements with bed tonno on?

I wouldn't expect to see any MPG improvement with the Tonneau on. I have an 03 as a personal truck and the tonneau makes no difference in MPG city or Highway. My 08 6.7 worker gets about 13 city, and 15-16 highway.

I guess thats really going to go out the window when I put the 33's on it!!!

I could possible do that if I drove 50 mph on the highway everywhere I went. I started keeping a log on mine at 3349 miles. My last entry was at 17,880 miles, I missed 4 entries so that ups my avg. just a bit I could do the math. I'm avg. 13.77 mpg all types of driving. Towing, hot rodding, town, grandpa. That's computer calc. with texas gas prices.com. Did the math anyways makes my avg. 13.97 mpg.

YEAH I definatly notice a difference if I'm heavy on the Accelerator....[nonono]

I would have to completely disagree with you. Then again it does depend on what kind of Tonneau cover you put on. I personally put a Pace Edwards jack rabbit I believe it's called. Its the Hard cover that rolls up toward the front of the bed. Yes I did loose about a foot of bed space... but I'm mostly empty so I'd rather have the cover.

I immedietly saw a 1-2 mpg difference!!! that works out to about 5-10% !!!

I'd say that's a savings for sure.... pays for your cover & then some in the life of the truck.

I get 18-19 mpg on the highway and 14-15 mpg city, haven’t done a full tank towing yet but I estimate it to be between 11-12 mpg. That's hand calculated, my overhead usually reads 1.5 mpg higher then what ever I calculate.