IAJack

Today on the way to and from work the trip meter said 2.5 miles and .2 gal. used which would be 12.5 mpg. ,but he trucks computer said I was getting 10.5
The outside temp was around 50F and really short trips like this are tough on mpg's. Are the computers in these things off that much or did it not even have time to caclulate the average mpg?

Shotokan1509

The computer is laughably wrong, how in this day and age something so simple can be so off is ridiculous. Mine is 1mpg optimistic and averages almost 2 unaccounted for gallons of gas per 36 gallon fill.

I average mid 13's non-highway, and decent amount of hills. Overall avg 14.3, worst tank ~12.5 best ~16.5. When i am on highway, I do not drive mpg friendly speeds

frosty19

Ecoboost crewcab/5.5ft box with 4x4 and 3.55 rear end.
Just did a run up to the cabin this past weekend (500km/310miles round trip) and averaged 14L/100km(almost 17mpg). Temperature was around -15*C(5*F)
Same drive this past summer netted me about 20mpg.

Just throwing it up for comparison. I don't do a lot of city driving but I would say that the average may go down 2-3 mpg at most so you're probably not far off doing short trips and warming the truck up that long in the mornings...

yoster

You have 3.31's like me. I also have falken wildpeak AT3W 33" tires. Even on OEM tires though, city MPG is horrible with 3.31's. The ONLY thing I've found to improve it is the 91 octane SCT CANNED tune. For some, odd reason, it gives better MPG than any of my custom tunes. Both city and highway. Granted, we're not talking major gains here.. and this isn't a 'save money' solution.

Highway MPG on 3.31's isn't great either. 60mph, sure, awesome MPG actually. Anything over that, and the 3.31's have the RPM's just low enough where it starts asking for extra boost from the turbo's to fight wind resistance, and down goes your MPG's. I've found 3.55 and 3.71 f150s to get better city AND highway mpg vs 3.31 oddly enough.

Spiky

Did you ever try turning off 6th gear? Could help to get the rpms vs boost just right. Or changing cruising speed by a mile or two. We used to do that in my dad's S-class in the 80s. The overdrive gear (forget, 4th or 5th) was too high unless steadily doing at least 70, preferably 80. He always told me to just keep it out of overdrive, apparently I wasn't supposed to do 80 at all. Shh.

Ricktwuhk

Let's play with math.

2.5 miles / 0.2 gallons = 12.5 mpg
2.54 miles / 0.151 gallons = 16.82 mpg
2.46 miles / 0.249 gallons = 9.88 mpg

It's the human that's off, not the truck. You are doing a less than exacting calculation with numbers that are to one-tenth. All 3 examples I gave are 2.5 miles (rounded) and 0.2 gallons (rounded).

Measuring MPG on a 2.5 mile drive will also vary tremendously, regardless of the math.

DNA Dan

I have a 2012 FX4 SCREW 3.73 rear with Stock BFGs and a topper. I make 4 short trips a day and average about 11-12 MPG. The truck is a hog on acceleration. Once I get moving, I can hit 19 on the freeway keeping it under 70 MPH. My assessment is it's the short trips that is killing your MPG. Did you drill the weep hole in your CAC? I also suspect it may reduce low speed acceleration just a little bit, combined with heavier tires = lower MPG.

Once thing I will say, (not to be "that guy") but if you make several short trips, I hope you're running a catch can of some sort. In winter (Pacific NW) I pull about 12 oz of fluid and condensate from about 500 miles of driving. If you don't have a CC, check your oil level and be sure it isn't diluted with fuel or condensate. That is really bad for the motor to have thinned out oil.

IAJack

I am in AZ where it is fairly warm most of the time so I am not running a catch can right now, but I am considering adding one as a just in case. I have the oil changed pretty often and use Motorcraft synthetic belend. A couple years ago when I lived in Iowa I had the gas smell in the oil issue. They performed the TBS for that and it did help some, but I keep track of it now and it is better in the milder temps here in AZ.

byoungblood

It is the tires. I put load range Es on mine about 2-3 years ago and lost about 1.5-2 mpg.I haven't hand calculated the mileage, but just going off of a long term observation of the gauge on the dash. I put those tires on there to try to get rid of some of the bounciness when I was towing my trailer, but only noticed a small improvement there. Probably should have just gotten some airbags instead. I will likely be going back to a stock sized tire when the time comes, even though you can't find any in load range E.

With the larger tires, I do notice some difference in my city mileage by using tow/haul mode. The computer is far too eager to shift into higher gear and lock up the torque converter at lower speeds, which has you in the gas more in traffic that is constantly slowing/speeding up. 6th gear/locked converter at 40 mph in a 6000# truck in traffic just doesn't work.

DNA Dan

byoungblood - LIke you I bought heavier, firmer sidewall tires to help mediate the bounce when towing. I have since installed the ride rite air bags and I can confirm they do more for the bounce than the tires did. It's not completely gone, but reduced it maybe 60-70%. What it does is it lessens the "effect" of the bump, so you'll still feel the initial bump, but you won't bounce down the road for 2 city blocks. I only feel about 2-3 bounces after hitting a whopper. These are stock sized BFG ATs. I think I will be going back to a P-rated stocker when these are toast.