Originally Posted by K80

MPG on these diesels are extremely variable; weather, wind, road grade, Ford reflashes to prevent head gasket destruction, tire size, tire inflation, type of driver, etc. For instance, a friend of mine and I took a trip to Florida last year, 1800 miles each way, and we each took turns driving as we drove straight through; 20 hrs. His method of driving was on the pedal and 5 second later foot off. That was his method; on-off-on-off. I mentioned to him that every time he took his foot of the pedal the tranny would come out of lock-up and it would take a few more moments to lock-up. I, in turn, controlled pressure on the accelerator pedal without a full release....he average 15.5 and me, 17+ mpg. So there is an instance where driving a certain way can influence mpg. It was also mentioned that brake calipers not totally releasing brake pads on the rotor is a factor on loss of mpg. This is true and it will directly influence mpg loss. This happened to me as well as others that have posted here. I guess it is wise to replace calipers when changing brake pads. Good luck in solving your low mpg. Mike...K80.

Originally Posted by run6.0run

I want to chime in,,, I roll 58 mph,,,,, everywhere,,,, loaded and empty. Granted,,, for a daily driver, stop n go,,, isn't the same as my operation,,, but if I'm under 19 unloaded,,, I'm unhappy. Mine is a 6 speed manual tho. I run 82psi in the tires. I also found,,, and proved it time n time again,,,, The more tread you have on the tires,,, the worse mileage. It's not smart to run bald tires tho,,, but the lower the tread,,, the better mpg's you will get. My mileage always drops with new tires.

If all else fails,,, n ur gettin bad mileage driving in the wind,,, I was told long ago,,, to turn around. Lol

Originally Posted by groy

What would you guess switching out to 3.73's gears from 4.10's...if it equates to the 4.10's running at 2,000 I get about 16mpg at 1700 it's over 17mpg close to 18mpg...works out about every 100 rpm = .5-6mpg...

Originally Posted by Big_Red_Brute

I called today and made an appointment with the Ford dealership for Friday morning. They're going to take it in and put it on the "machine" to check all the dianostics of the truck, and check for any upgrades for the computers. They're also going to replace the fuel filters while its in there. The upgrades helped my friends truck last year after he had them done, so that's what I'm going to try. I will let everyone know if it helps/hurts the truck.

Originally Posted by Maxium4x4

If you were ordering a truck it would be an option. If the truck has 4:10's...you would have decide longevity of ownership against the price of fuel you would save to pay off of the initial investment to the gear change.

If I confused you I understand....... Gear change would buy a boat load of fuel unless you are in a situation where the gears are damaged.

Originally Posted by uncle_jessie

I just took my truck from TN to Charleston SC. Ran 2 tanks and she averaged 16.2 mpg with the cruise set between 70 and 75mph. With driving through the mountains of eastern TN and western NC. Not to bad I don't think for a truck that big. F250 4X4 CC SB. Family of four and all our luggage. I'll take that!

Originally Posted by uncle_jessie

I really wasn't expecting it to do that good. But I remembered reading this thread, so I kept the boost under 10psi and stayed at a steady speed as much as possible. All this was hand calculated to as I don't have a economy display.

Originally Posted by groy

Do you put anything in your fuel?
Do you what size you’re drive gears are?

Originally Posted by uncle_jessie

Yeah she gets a bottle of Diesel Kleen at every fill up. And my rear axle is 3.73 LSD Awesome matic transmission