i have a 2002 f-250 diesel 4x4 four door with a lift kit and big tires. my 7.3 is stock and i get about 11mpg. i have heard all kinds of advise including one guy that swears he gets 25mpg in his but spent 3000 to do it. I'd spend that much if it was a sure thing. (can't find that guy anymore) what can i do to get better fuel economy. I'm not real worried about power, it has plenty. all advice is accepted just please don't be so general that you leave me still in the dark. thanks in advance. mike

 

I had a 2001 7.3 4x4 that I just got rid of that I averaged 20 mpg with, mostly at hwy speeds below 65 mph with just a few stop lights. It was stock with the exception of a $300.00 DP tuner economy chip. It was not lifted and I drove it easily to get that kind of mileage. My commute was also about 32 miles each way. Driving more stop and go with shorter trips it averaged about 16 mpg. If I got it out on the interstate and kept it under 70 mph on a longer trip like from NC to Fla I could get 24 mpg if traffic was light.


My new 2015 6.7 has only gotten a best of 16.8 mpg. That was when I drove it home from the dealer 168 miles and I found out the front hubs were locked in. I never got it above 65. I recently got 16 mpg but had run 79mph for much of the trip and had a regen. I hope to get it up a little, but time will tell. It has about 1400 miles now.

 

Maybe on the highway, after he's already warm and up to speed. Average? Not possible. It makes a big difference what truck you have. A regular cab 2WD XL weighs almost 2000lbs less than a crew cab long bed 4WD with all the options.

My regular cab 2WD XL (the lightest one you could buy from Ford) with a 6.0 could get about 21mpg average only on the highway if I tried really really hard. A 7.3 would get less than that. That's with no load and really small tires/wheels.

General maintenance and tuning can get you a mpg or two, but your truck just wasn't made for that.

 

Ain't no way you'll ever be able to even smell 25mpg. You won't even get into the high teens with the lift and tires. There's a lot of BS floating around about these magical 25-35mpg diesels that just flat out don't exist. If there was a $3000 kit that made 7.3s get 25mpg every guy on FTE, .org, PSN, PSA, and a dozen other forums would have them, and probably be selling their own version for less.