I have a 2005 f350 with a 6.0. I only get around 12 miles to the gallon. I hear people getting any where from 16 to 22 mpg. I just replaced all the filters fuel and air but not a big change. I am considering a tuner but I've heard they don't really help fuel mileage. Any ideas? I think my power is suffering a little bit (not sure) I thought maybe I would clean out my turbo. Will the turbo need cleaned even if the vehicle doesnt throw any codes?? Would a dirty turbo decrease fuel mileage?

 

It might be time to have some diagnostic work done to make sure everything is working up to par. As you are probably aware a lot depends on where you drive, what you do with the vehicle and if proper maintenance has been done based on the mileage.
Has the mileage become progressively worse or has it always been low?

 

I bought the truck last april from texas and drove it to new york. The truck appears to be very well maintained. There were a lot of maintenance records done with ford on car fax. I do mostly street local driving. It has never been great it always has been around 12 on the hwy she will go up to 14 or so. there is 125,000 miles on her. what do you mean diagnostic work? bring it to Ford? If so what do I ask the to do?

 

Could it be possible it was a work truck used in the field and has a drivetrain set-up for pulling power and not mileage?

 

That could be!! It did have a 5th wheel attachment when I got it. How would I check that or Even change that. Would that be a tuner?

 

I don't know how much if at all a tuner would help, but the differential on the rear might reveal some better info. The coding on the driver's door should tell you what rear was built into the vehicle and looking up the code could provide the ratio. Don't know if there were other ratios available at the time it was built. A good start would be to determine what is in it right now.

 

My 05 gets about 13-14 combined city/highway and close to 17 on the open road. I'm rarely 'completely' empty though. The SD is like a brick moving through the wind, and your best mileages will be seen 55-60ish and as you push harder at speed, the mileage tends to suffer some. Environment and driving conditions weather towing/loaded and terrain will impact mileage stats quite a bit.

Before the ULSD cetane drop/sulfur reduction some of the 7.3's would crest 20-21+. The 6.0 would be very hard pressed to get close. 6.4 even worse. I don't know of any 6.0 owner closing in on the 20mpg range. My 6.0 runs a Diablo Predator tune, and I do see a small increase in mileage over stock programming, however, the power gain if towing or in hard throttle situations (if you like to use it) can easily remove the added increase. Usually what you see with a tune in the lower settings is more power with no loss in mileage. Any power enhancement may come with a risk though given the 6.0 history. Something to consider when adding HP.

Your truck is stock, no large tires ect.?

 

I have a 2016 F-350 SRW, all stock with a 6.7 in it. My mileage is low too. I just had to have the whole exhaust system replaced. I sure was glad that it is still under warranty. The DEF pump went out and the whole system needed replaced to the tune of $6,000. I don't drive it very far every day, apparently not far enough for it to get hot enough to burn the gases off.

When I first got it back, it had awesome power and the mileage was great. It has dropped some now. After reading about the ratio of the differential and being setup to tow, I'm wondering if that is the case. I know when we bought it new, it had on the sticker that it has the camper package. I have the window sticker saved in a file. It says it has a 3.55 electronic locking axle. That sounds like the front axle. I'll look on the sticker on the door post. I pull a 39' toy hauler fifth wheel with it and it doesn't have any problems. We pulled the trailer over the Rocky Mountains and it didn't have any problems.

Maybe I'm not going to get the best mileage but I sure can pull that beast of a trailer!

Haulinit