So I have had my truck for right at a month now and put on about 1500 miles. I drive pretty hard... I guess, and it's been really cold and windy so I've been letting my truck idle a lot. First tank I got 15.7, second tank 15.1, and this last tank I got 14.1. On this last tank the truck idled more than normal cause it was like 5 degrees and I hate cold weather. Overall I guess I'm impressed cause none of my other gassers have done this good with mainly in town driving. Oh and for the guys that are wondering I don't go my in dash meter, this is all hand calculated. That thing is about 1 1/2 mpg off in my truck.

 

Actually I figured it would be more. What's your truck configuration.

Mine is a 2010 5.4L Screw 4WD 3.55LS 5.5' bed with a tread act sticker payload of 1430# (5770# truck weight). I just turned 2000 miles.

I'm getting in town 15 mpg and in mixed driving 16.5 -17 mpg with idling in the winter. Temps have been -7 to 25 degrees F. My MPG display was off by .7 mpg. It displays a lower mpg than I'm getting so that's .7 additional mpg. My 2008 Sport Trac with the 4.6L 3 Valve V8 did .5 mpg better so I'm really impressed with the fuel effeciency as well.

 

Mine is a 2011 FX2 screw with 20's

 

Are you filling up at the same gas station? If not, that may be your reason for changes. Some brands blend more ethanol which causes your mpg to drop, Just a thought. More idling will definitely affect your mileage.

 

My third tank of Shell 87 (E-10) gas was 17.88 mpg (avg. comp. read 18.3 mpg) in combined driving.

 

With winter driving here and the additives in the gas, we get terrible mileage. Those numbers you threw up are what I should get in better weather as winter usually drops the mpg down 1 to 1.5 mpg. I'm also at very low mileage. I've seen mpg get better with all my vehicles when mileage was over 5,000.

 

I have always heard that mileage improves after break in but personally none of my vehicles has changed much. That said, my new F150 gets about 2mpg better than my 2000 f150 and I am elated.

 

do u reset the mpg at the gas pump before driving off or after you've left? makes a huge difference on how it reads(obviously resetting at the pump is the accurate way, not once you have a nice roll going)..mines pretty much spot on

 

My first three tanks are averaging the same as my '07.5 STX SCab with 40K miles, 3" Catback and programmer. I'm confident it will do better as I continue to drive.

 

Pure Gas I have gotten. 18.1 and the lie o meter said 18.6 and 17.1 and the lie o meter said 17.5.
I have a Plat with 3.55 ls

 

I have not reset it ever since I've bought the truck. That should be the most accurate over all. Besides that I hand calculate, no room for error that way.

 

Wow... Surprisingly un-impressive fuel economy numbers from the 5.0...

I average 17.5 mpg (hand calculated) with my 2005 with the 5.4 and 3.55 gears and running an 87 high performance PHP custom tune with 97,xxx miles on the clock, filling up at the same Texaco station every time for about the last six months.

 

I don't know why y'alls MPG readers are so off. I reset mine every time before I drive away from the pump and it is very accurate.


I guess there are two ways to use it. If you want to see how much you are getting per tank you should reset it and if you want to see what your truck gets over the course of its driving life never reset it.

 

My 2010 4x4 with 4.6L 3V gets about 16.5 overall in winter and 17.5-18.1 in Summer non-towing, so far. I have the 6 speed trans with 3.73 axle. I got 13.6 last September towing a 68 Mustang on a dual axle trailer from Lexington Ky to Canton Mi.
You should be getting better than 15.1 in mixed city driving and no towing. I get 16.5 towing a boat! Try to drive easy for a tank and see what you get.

All hand calcs on MPG . My in dash meter is always 1.5 MPG off

 

Actually the lie o meter is showing total average since you bought the truck and when u hand calculate you are checking by tank. Try resetting at the pump before u drive off and check it again when u fill up. Mines been very close every time that way. I have trip 1 as my since I bought the truck average fuel economy and it shows 16.9. But when I reset trip two when I fill up it'll show 15... Or whatever it is because it only has my last tank history. Try that and see if it's accurate for u. That's probably why it was accurate on your first tank but off after that.