I've got an 04 with the 35 gallon tank. My best tank was 20.2 mpg in the summer, and the worst has been 12 towing my sled trailer in the dead of winter. The colder it gets, the lower the mpg go. I usually see 13-14 in winter, and 17-18 in the summer.
I've got a scab, 4x4, and 3.73 rear end.

 

Short trips can really kill mileage. Usually the engine is barely warmed and running at peak efficiency by the time you hit your destination.

I get good mileage on all my vehicles due to driving style and a 23 mile commute one-way. I work with a couple guys who have commutes in excess of 70 miles .

 

All these whacky ways...

Simple - fill the tank, drive, fill the tank again. Divide gallons into miles. Brand of fuel affects my mileage by almost 2mpg. Brand-name gas gets me around 17, and off-brand usually gets me around 15. 01 Screw, 4x4, 5.4, totally stock.

Those are averages for normal daily commuting. Straight highway I can get over 18.

 

I have a 97 4x4 with 127000 miles on it. I drive it easy and am always looking to get a few extra miles out of a tank of gas.

I always run Super (engine pings if not ) In town I'm getting 10-12 mpg. On the highway its 16-17mpg..

 

for the record, I usually run 87 octane as directed by the manufacturer, and I agree with some of the others that brand does matter as does the station that you buy it from.....just like the gas tank that is on our trucks the fuel storage tanks at gas stations accumulate the same sediment over the years so I usually try and go to the newer stations if at all possible. nothing against the mom and pop stations just my preference.

My job depends upon math so I think i am doing the math equation correctly miles driven divided by the gallons put in to fill the tank equals miles/gallon. I have checked the in dash computer vs. my calculator and they match so no reason to doubt the computer until I find different.

Correct tanks size doesn't matter, I was simply stating the potential range of miles that I could drive, I rarely drive until the tank is near empty...usually refill about 1/4 tank remains so not to pick up bottom scum from tank as suggested above.

 

I get 18.5 highway driving 75mph and 12.5 city driving fairly easy.
I even have the 5.4 with 33" mud's. I guess I am one of the lucky ones.

 

actually, it would be the scum at the "top" of the tank you should be worried about your fuel pickup always stays at the bottom, which means anything at the bottom will be picked up regardless.... i think the biggest problem with running down to empty is the water that accumulates at the top... correct me if im wrong, but isnt fuel denser than water? causing is to push water to the top? never tried that experiment, but it sounds right... cant remember off hand though, but i would honestly say it couldnt hurt running down to no gas every once in a while.... clean out your tank... and since nothing from the tank is going to make it passed the fuel strainer, or the fuel pump, or the fuel filter and into the motor, i think you can safely say that your tank going down to bare nothing isnt going to hurt anything worst case scenario, you jam up the pump (assuming the strainer lets something past it) and have to buy a new one.... thats about all i can see... aside from that? i dunno.... maybe in excess, water could damage the motor... but really, condensation isnt going to accumulate to be THAT much, and if you are that worried about it... you can always use fuel line water remover

 

No fuel is lighter than water so if the fuel were to seperate the gas will accumulate on top, for example the exxon Valdez...the huge oil spill in Alaska....oil floated on top of the water. I am more concerned about the heavier particulates in the tank.

I don't question the ability of my fuel system to filter the crap out before it hits the pump and injectors, just feel that it is unnecessary to run it down that far and subject the system to those contaminents. thats all. Besides for as much as i drive, the gas doesn't have a chance to seperate.

 

separate? man... in a truck as new as yours, if you have crap in it... i think its time you either took it off and cleaned it out, or bought a new one..... the gas tank in my 1972 nova didnt have anything in the tank but gas.... and it was a junkyard salvage before it was... what it was when i finished it

 

and yes, i know oil floats.. but from what i have been educated on, fuel is the byproduct of oil... its whats taken out of oil to make it usable in autos... otherwise known as the "waste product" i heard back before gasoline engines, refineries used to dump fuel by the gallons into the river.... because there was no use for it... of course this was MANY years ago, but i figured that gas, being separated from oil, would have different tendancies... im going to run a little experiment tomarrow.... ill let u know how it came out

 

water is heavier at 10 lbs/gal, gas is around 6lbs/gal and diesel is roughly 8lbs if memory serves me correctly. the water stays at the bottom of the tank.

as far as mileage, I get about 17mpg, mixed driving from my 97f150xlt 4x4, 4.6-5speed.
my driving habits are pretty conservative.

 

nice ride.....I know that my tank and everything is pretty new and that is not my worry at this point. But I am more concerned about the crap that will accumulate over time, my dad had a '73 ford handed it down to me and I ran it til it was ready rust in half. Had to replace the tank on that truck once as it had developed a series of pin hole leaks along the strap that holds it in place ...there was crap in that tank. the stuff was larger than the pin holes so it didn't come through the holes. So I am just trying to prevent this from being a problem. thats all.

 

you think thats a nice ride? lol yes it is.... but wait till you see my camaro... lol god i miss this car... too bad the head gasket blew

this was my camaro

 

but back on topic, your fuel tank should be fine man if your truck survives the next 30 years, do it the favor of giving it a new gas tank lol its the least you could do.....