Mine is completely stock except for the exhaust. I get about 15 around town on E10, and my highway mileage generally is in the 18 to 20 range. I've seen as low as 12 and as high as 23.

 

Even with a lift & 35" tires, I get about the same at highway speeds. Just don't even think about what my stop & go driving nets.

 

Are most of these figures for 2 wheel drive? I have a 98 F-150 4+4 Reg. cab, long bed. I don't think I've ever got more than about 13 or 14 driving it very easy...Obviously not in 4 wheel drive.....Does this sound right?

 

This is about where I'm at in my '99 4X4 short bed. I know this doesn't sound right, but when I first started driving my truck (my wife drove it almost exclusively for the first 2 years I owned it), I drove it very easy and got 9-10 mpg. After a while I said screw it and started driving it a little harder ... mileage jumped to 13-15 mpg

On a side note, this thing gets really bad mileage in 4wd (slowly driving dirt roads). My last 4X4 truck got about the same off road as it did on the highway. I'm thinking the auto trans really kills the mileage when you're crawling along in 4wd

 

I've noticed my truck down shifts alot....While at steady highway speeds. If there's any kind of uphill grade it's always downshifting. Come to think about it it evens down shifts on level ground alot more than I think it should...

My 88 straight 6 with the 5 speed got better MPG

 

the gas mileage was worse until 2000 or 2001. my 04 heritage saw a consistant 23.5 combined driving but never took a long trip to see what it did on the highway. my 08 has seen a best of 21 so far. worst was around 16 on the highway going about 75mph with a 40-50mph headwind. i was even drafting off of another truck. and worst while towing a uhaul was about 14mpg

 

You got 565 miles out of a tank of gas? I wouldn't believe it unless I saw it

 

i never dropped that truck below a 1/4 tank tho, but i remember hitting 450 before filling up. i watched it for 3 consecutive fill-ups and every time it was 23.5. after that i just filled up and checked it occasionally. i know it dropped to about 19 from 490Lbs in the bed and the winter mix fuel in it plus a few minutes of warm-up time. i know you guys have commented on this being BS before, i dont have the truck anymore so i cant prove it and i wish i could have taken it on a long trip to see what it did on the highway but it never happened. only thing i can say is it was my truck, i know what it got for mpgs and thats all the approval i need. dont care if anyone else believes me or not

 

i wish... more like 15 - 18 for my regular cab, long bed v6