kayt425

I filled up and ran my last tank of gas. the readout says i burned 27 gallons of fuel, but i only have a 26 gallon tank. I am only getting 14.5 MPG at the BEST. I found this interesting. Have had the RPM revvving problem on startup. Pics below:

ajrothm

Mine is off as well.... It doesnt read high like yours but it actually reads lower then the fuel pumps I fill up at..... I have gone to 3-4 different gas stations to fill up, it almost always takes 24.0-24.6 gallons to fill up per the pump's read outs..... The gallons consumed per tank on the dash display is always almost .7-1.0 gallons LESS..... So if the pump says 24 gallons went in, the eco display says I consumed 23.....thus making the mileage look better then it is..... All that being said, I am only getting 15.5-16.5 mpg average on the display at each fill up.... by hand calc...its 15.0-15.5....

I think its Ford's way of trying to make us feel better about our purchase....

Riccochet

When I fill up my display is only off by maybe .2 to .4 and the MPG is almost dead on. I average around 20mpg with mixed city and highway.

shaginwagon

Same here, fuel consumption always shows more used than actual per pump reading. Averaging 15mpg in city driving.

blueoval28

I am the same as this. I have yet to find that the computer is off more than .2 to .4.

Razorback150

OP you have aftermarket wheels and tires, all talk of MPG's is irrelevant. My FX4 is stock and the avg mpg reading is never more than .1mpg off, from my hand calculations. Even if you got tires that are the exact same size(most people don't) as stock, there can be variations in manufactures sizes, resulting in the odometer being off. And any additional weight in rotating mass will result in a loss of mpg.

blackknight87

when i fill up my 5.0, my the computer usually shows that I burned about .5-1 gallon more than i actually fill up. this leads the computer mileage to be a bit lower than when hand calculated.

ElGordoTejano

It's all computer controlled. It's always going to be inaccurate. Plus the computer controls the MPG it wants to give you all depending on your foot. If you lay soft on it and get it to 22mpg, then keep going and slowly raise speed from like 65 to 75, it will average from 21 to 22mpg. But if you start out bad and only get like 18, or 15, then it stays like that even if you coast down to 60-65. So it's the computer that determines what you really get. I have been fiddling with this for a couple of weeks and it does it every time.

I got 24.3mpg into work this morning. Imagine that. lol. I was getting crappy mpg until i hit right around 3700 miles. Now it just varies. But i am well aware now how to trick the computer to give me better.

2011FX4SC

From the manuel.
Filling the tank
The advertised fuel capacity of the fuel tank on your vehicle is equal to the rated refill capacity of the fuel tank as listed in the Maintenance product specifications and capacities section of this chapter.
The advertised capacity is the amount of the indicated capacity and the empty reserve combined. Indicated capacity is the difference in the amount of fuel in a full tank and a tank when the fuel gauge indicates empty. Empty reserve is the small amount of fuel remaining in the fuel tank after the fuel gauge indicates empty.
The amount of usable fuel in the empty reserve varies and should not be relied upon to increase driving range. When refueling your vehicle after the fuel gauge indicates empty, you might not be able to refuel the full amount of the advertised capacity of the fuel tank due to the empty reserve still present in the tank.
For consistent results when filling the fuel tank:
• Turn the engine/ignition switch to the off position prior to refueling, an error in the reading may result if the engine is left running.
• Use the same filling rate setting (low — medium — high) each time the tank is filled.
• Allow no more than three automatic click-offs when filling. • Always use fuel with the recommended octane rating. • Use a known quality gasoline, preferably a national brand. • Have the vehicle loading and distribution the same every time. Your results will be most accurate if your filling method is consistent.
2011 F-150 (f12) Owners Guide, 3rd Printing USA (fus)
401

Jay03GT

If you truely went 406 miles on one tank, you are getting a shade better than 14.5mpg.