My truck seems rather accurate. The most it is ever off is about 1/2 gallon, I figure that is with in the variance that the nozzles sensitivity will click off at.

 

Same problem here. 2014 was almost dead on every time. 2015 filled yesterday, said I used 13.8 gallons, took 15.2 gallons. I was hoping the difference was just using remote start too much, and the system doesn't calculate for that fuel used, but now I worry that it's a bigger problem. I don't understand on so many of these options on the new trucks how it seems they can go backwards in technology.

 

Wow, this is crazy. I literally just signed back in after a year in order to post about this EXACT topic.

I too have a 2015 5.0 with a 36 gal tank, and I've found that the dash/gauge numbers about about 1 MPG LESS THAN what I hand calculate, and the gals. used are around a 1.5 gal average LESS THAN what I actually fill up with. As far as my fill up procedure, I'm only filling up until the nozzle clicks, let sit for about 10 sec, then one more pump until it clicks again (about 0.5 gal).

These are the values I've gotten so far since taking ownership of the truck in late October.

 

I have the 2013 with the 36 gallon tank.
Usually I get about 1-2 gallons more in the tank than display says I used and also the MPG has always gotten a better reading than by hand up to a 1 mile of but usually 0.7 - 0.5.

 

This is getting interesting. Sounds like this issue is mainly happening with the 36 gal tank.

I don't have an issue with the MPG being off, but I can see someone getting into a pickle if they are trying to stretch a tank of gas to its limits, and running out of fuel when the truck says they still have another gal or so left.

 

I would say mine is within reason. I have a 2014 with the 36 Gallon tank. From the fuel light kicking on to filling up (I let it click three times at the same pump), Pump says .7 of a US gallon more pretty much every time. I don't always let it get that low, but it is still off by .5 gal anytime I let it get under 1/4 tank.

Not perfect by any stretch, but close enough for me as I hand calculate anyways.

 

I'd never let mine get low enough to be a problem but when I filled it up with a half a tank on the gauge it took almost 2 gallons more than it said it had used. Mine is a 36 gallon tank.

 

I had an issue not long after I got my truck that it said it had 16 miles left but stalled immediately after starting it in the morning on my driveway. Which is not very steep. I coasted down to the street, and it started and got me to the gas station which was right down the street.

 

Mine is the 23 gallon tank. My 2014 was the 36 gallon tank and was almost dead on every time. A bit frustrating that it's almost 2 gallons off on a 15 gallon fill up.

FYI, putting a 23 gallon tank in these trucks might be the dumbest thing Ford has ever done, either that or I am dumb for letting the salesman convince me I would not regret the smaller tank... Live and learn I guess.

 

I too think that was retarded. I guess they thought since these 2015s are more "efficient" that you didn't need as big of a tank.

I love my 36 gal and wouldn't trade it for any other feature offered on these trucks.

 

Anyone here consider the issue may be the pump? May want to look at whether the regulators in you area test at five or ten gallons, then check using that quantity at various gas stations.

Sometimes pumps are just off, sometimes you are being ripped off.

 

After I took delivery of my 2015 I was flipping through the various gauges. I noticed Trip 2 had something 72.8 miles. The main odo had 72.5 miles. That got me scratching my head. A few days later I was flipping through again and noticed the difference between the two was closer to 2 miles with the Trip odo being higher. I figured they would use the algorithm for all of the odos, so they should be coming up with the same numbers.

 

I've filled up at gas stations 300+ miles apart, and they were off by the same amount.

 

I haven't noticed this, but I will take a gander at it the next time I fill up.

 

Next question would be: Exactly how does the system measure fuel used, and how does differing fuel densities alter this measurement? Highly accurate fuel flow meters used in aviation and racing are very expensive devices.