My 2015 F150 SCREW Lariat was great, I loved that truck however last December is was stolen. 10 days later it was recovered. Unfortunately it was beat to hell. I got a reasonable offer from the insurance company so I went out shopping for another. I ended up finding a similar 2017 Lariat with only 11k on it. Like my 2015, it was Magnetic Metallic, had the 4wd Sport Package, off road package and tow package. What was different was the 2017 had the 6'7" bed instead of the 5'6", and a 3.35EB with a ten speed trans over the 2015's 5.0V8 with a six speed trans. Funny thing was I figured that I would be getting better mileage from the new truck. No such luck. The 2015 with the 5.0V8 was averaging about 16.8mph. The new 3.5EB appears to be getting about the same. I tend to be a feather foot, I don't jump on it to much. I actually have the gauge set so I can see what the mileage is in real time. I often adjust my foot to try to keep it above that 16.8. I've had this truck since January and probably put 5k on it. After first couple months I though it was because I hadn't put a new tonneau cover on it yet but I did and it didn't really seem to change it that much. I even have the same rims with ko2's on it.

How is everyone else's experience?

 

Although fuel mileage may not be an improvement on the face, the 3.5 w/10spd would shine if you do any towing. What rear gear did each respective truck have/has? Also the fuel economy guage aka lie-o-meter isn't foolproof accurate. Hand calculating and adjusting the indicator may be neccesary. This 19 says it gets about 1.2 mpg better than it actually does, my 12 the indicator said it got worse than it actually did. Just need to go into engineering mode and tweak it.

And fwiw this 19 gen 2 w/10spd so far in 1800 miles is getting about 18.5 all around average, and I'd say I have a pretty even mix of highway and city driving.

 

Much better, thank you!

 

helpful...

 

I have a 4x4 screw 5.5' box with a 3.5eb/6spd and get around 20mpg mixed driving. Best trip was 23.9mpg driving 399 miles

 

Mythbusters debunked the 'covering the truck bed' fuel mileage myth like back in the early 2000s.

My FIL with XLT Screw Sport FX4 gets over 20 on his 3.5EB. sometimes feathering the throttle/super slow acceleration isn't the best. Efficiently getting to cruise to allow for the lower consumption under lighter load...that's the optimal path.

Anyway, check tire pressures? LT tires or P-rated tires?
GL.

 

LT, I'm running KO2's

 

Tires could be a lot of it unless you had the same tires before. One magazine did a test and LT Tires cost 2.0 mpg if memory serves due to the deeper tread (higher rolling resistance) and weight. Then add in an aggressive all terrain tread and it's that much worse.

If you are running lower speeds and lower rpm, 3.31 gears you may be seeing to much boost (especially with more rolling resistance). Try locking out 10th and see if mileage improves. My 18 does better in 9th on 55 mph roads with a headwind and that's with stock tires and 3.55. I have averaged 19.7 mpg lifetime (non-towing) with mine.

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Not exactly comparable, but I've had a '16 for 6 months and just got the best mileage ever at 16.4. I guess the 3.5EB motor is not designed for a 4 mile commuter vehicle. I now drive further to only go to trails when I get to run or ride a bike. No more to/from work and lunches. Now it's just to grocery store every week or two, or a few rides a week.

This is the worst MPG vehicle I've ever owned. No I don't need a prius, I would just like more than 14 mpg.
I've said it countless times, just so I don't get told how to drive -I could drive with you in the passenger seat with a hot coffee and you'd never spill a drop. LOL

It is what it is, nothing really I can do about it. The only tip I have is to stay out of boost but it's hard to do. Boost is always required, so it's up to you to adjust your foot to use as little as possible. For best results, of course. It's a joy to drive but the fun is taken away when you have to be so gentle with it.

Anyway....enjoy the truck. You have a lateral move so it's not really 'bad' when compared to somebody seeing about a 4 mpg hit.

 

KO2's can drop your gas mileage - especially if they are E rated instead of C rated.