Gas Mileage pretty bad pulling a trailer

[RickBullotta]

Taking a 2 week trip pulling a trailer with the 2021 F-150 Lariat 3.5 Ecoboost. Picked up in Minneapolis and heading to Montana and then return via SE ND. Anyway first day pulling a trailer on this trip. Slightly uphill most of the way and cross or head winds at least half of the way. Gas mileage was pretty low, avg 7.3 mpg and this is with speed avg between 58 and 63 mph. Pretty disappointed. Not sure if there is anything I could do to improve mileage. Trailer length is 23, weight is 4400. Not using a WDH. Any suggestions?

Is your truck stock of lifted/modded in any way?

Without the WDH you may be riding nose high and really killing fuel economy. Take some measurements of front and rear wheel well height with the trailer on. Our trailer is the same weight, and I can get 12.5 mpg at those speeds and 9-10 mpg at 75 mph. My guess is that the elevation change is what got you, plus the possibly the aero effects of not being level.

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[Chads first F150]

I just returned home from a 3000 mile round trip, towing a relatively tall wedge nose trailer. We hauled four people up front. In the trailer; three dirt bikes, and all gear for a weeks worth of riding and camping out.

On the way there we averaged a little over 7 mpg, running about 70 to 75 mph.
On the way back we averaged a closer to 9 mpg, running about 70.

The differences:
- I used 93 octane coming back.
- I turned off the cruise control coming back. I'd intentionally lose a little speed going uphill and gain a little speed going downhill. The cruise control seemed harsh; like it is mashing on the accelerator to get back up to speed / maintain speed going uphill.

Also noted:
- Bluecruise didn't work with a trailer.
- Lane keep assist would cause the rig to sway significantly, making it unusable.
- The Ford navigation would make an annoying 'bong' notification for upcoming bridge heights, until we found out how to turn off the 'trailer routing' feature.

I've been reading various threads here while waiting for my 22' F150. Finally got tired of waiting and bought a used 21' for this trip.

Thanks to everyone for all the good information over the past year or so!

 

[Mosey]

Air to fuel ratio. I get it. But is there a real world difference in mileage by locking out OD versus letting tow/haul operate as designed? The truck was new (to me) at the time and I guess I was paying more attention to the gas guage than what gear it was in. Was sure the mileage would be less than the "Not-so- Duramax", but wasn't expecting single digits.

To clear a few things up, I run in tow/haul AND lock out 8-10 at highway speed. Without extensive testing, anything you read, including my comments, are antidotal at best. Yes, I too was hoping for better.

I pull a tall cargo trailer and average about 10 mpg. My previous truck, a 2015 Canyon, also got 10 mpg towing the same trailer. The big difference is the engine in my F-150 is not working anywhere near as hard as my Canyon did. The Canyon would get my attention when it decided to downshift to second at 65 mph. As a side note, my Canyon would consume a quart of oil every 1,000 miles when towing.

 

[powerboatr]

Air to fuel ratio. I get it. But is there a real world difference in mileage by locking out OD versus letting tow/haul operate as designed? The truck was new (to me) at the time and I guess I was paying more attention to the gas guage than what gear it was in. Was sure the mileage would be less than the "Not-so- Duramax", but wasn't expecting single digits.

yes
tow haul will let it upshift to 9 and 10. depends on factors of road, incline, wind , speed, tires , etc
by locking out or inhibiting upshifts to 9 and 10 or even 8 will let engine turn RPMS that let it work more efficiently, with less down shifting and revving and unlocking tq converter
look at EB torque curve and thats where you should try to run engine to gain efficiency
i used to have a copy but not sure where it is now
i am sure google has millions ?

iirc peak tq is in 2000 to 2600 range 2500 seems to be jumping out at me but i have slept
so running 1800 -2000 rpm or so is letting it breathe and still be fairly efficient
each load up is different you just have to experiment on your set up to see whats best for you
for me if i am stuck in a 60 mph area i will lock out 9 and 10. makes a world of difference in smoothness of truck.
and stops the downshift , upshift, downshift at each incline or hill.
at 70 and empty then i leave all gears available
but i have 3.31 gears which are pretty tall imo
but the ten speed has such great ratios it allows you to use the other gears to make up for the tall rear

 

[tony72cutlass's']

I find that I rev pretty well with the 373 and have not found the need to lock out gears (other than playing with the feature, wife’s words not mine lol)

 

[powerboatr]

I find that I rev pretty well with the 373 and have not found the need to lock out gears (other than playing with the feature, wife’s words not mine lol)

i had 3.73 in my 4x4 expedition MAN it pulled like a freight train

 

[Xchevyguy]

powerboater, thanks that's what I asking about. Not sure the old Duramax/6 speed ever hit top gear in tow mode, maybe downhill. So a bit surprised the EB will. We shall see.

 

[Gros Ventre]

Wind resistance makes a big difference. More than just the engine design. I have a 4.6L DOHC Mustang and it gets on the highway the same mileage as the 2.3L DOHC Escape Hyrbid, both around 26 mpg. One is sleek and aerodynamic the other has the proverbial aerodynamics of a brick. If you then get the F-150 up on the turbos, there's another penalty. In order to get that turbo boost, and it is impressive by any measure, the physics of turbo-charging to prevent detonation calls for enrichening the fuel-air mixture beyond what a normally aspirated engine would call for at a given power level. That's just life in the big city. Go look at Ford's towing guide... buried in it is a limit on trailer frontal square footage. I've towed a U-haul open top trailer with a ramp. No more than maybe 1500# in it, but that big ramp sticking up in the air flow back there means that the best I got was maybe 12-14 mpg. ...And then I was going 5 mph under the speed limit... Those turbos are wonderful, they give you more power than you need and when you need it, it's there... But that power means burning fuel... Get over it.

 

[Tosh]

2021 Powerboost pulling 5,000lb 2022 Escape 21NE - average for 970 miles - 13.3 MPG, over hills and dales, not exceeding 62MPH.

3:73 rear, Tow-Haul mode, not locking out any gears, truck and trailer are level when hitched.

A standard 3.5 Ecoboost should get no less than 12 MPG under the same conditions.

 

[tony72cutlass's']

Wind resistance makes a big difference. More than just the engine design. I have a 4.6L DOHC Mustang and it gets on the highway the same mileage as the 2.3L DOHC Escape Hyrbid, both around 26 mpg. One is sleek and aerodynamic the other has the proverbial aerodynamics of a brick. If you then get the F-150 up on the turbos, there's another penalty. In order to get that turbo boost, and it is impressive by any measure, the physics of turbo-charging to prevent detonation calls for enrichening the fuel-air mixture beyond what a normally aspirated engine would call for at a given power level. That's just life in the big city. Go look at Ford's towing guide... buried in it is a limit on trailer frontal square footage. I've towed a U-haul open top trailer with a ramp. No more than maybe 1500# in it, but that big ramp sticking up in the air flow back there means that the best I got was maybe 12-14 mpg. ...And then I was going 5 mph under the speed limit... Those turbos are wonderful, they give you more power than you need and when you need it, it's there... But that power means burning fuel... Get over it.

Agreed, better to tow with something capable that burns fuel rather than these guys you see with 4 banger SUVs towing a 20 foot camper and wondering why they got no giddy up

And then their transmissions explode lol

 

[MikeA]

Taking a 2 week trip pulling a trailer with the 2021 F-150 Lariat 3.5 Ecoboost. Picked up in Minneapolis and heading to Montana and then return via SE ND. Anyway first day pulling a trailer on this trip. Slightly uphill most of the way and cross or head winds at least half of the way. Gas mileage was pretty low, avg 7.3 mpg and this is with speed avg between 58 and 63 mph. Pretty disappointed. Not sure if there is anything I could do to improve mileage. Trailer length is 23, weight is 4400. Not using a WDH. Any suggestions?

When I pulled a Rockwood 2104 21 ft "5500"lbs with my 2015 3.5 ecoboost screw my mpg dropped from 18 mpg to 9 mpg and I ran about 70 most trips so yours does sound a tad low. btw I had the 3.55 gears. this was all within 150miles of bham Al.so not a lot of hills.

 

[Gros Ventre]

When I pulled a Rockwood 2104 21 ft "5500"lbs with my 2015 3.5 ecoboost screw my mpg dropped from 18 mpg to 9 mpg and I ran about 70 most trips so yours does sound a tad low. btw I had the 3.55 gears. this was all within 150miles of bham Al.so not a lot of hills.

In my case out here in Wyoming, we don't hill climb, we mountain climb... Some climbs are a bit longish... And we're at altitude... so the turbos kick in earlier... And we have winds out here. I've had a headwind on I-80 drop mpg to 17 with no trailer and a light load... But I have all the power I need!

 

[tony72cutlass's']

At least we’re not this guy..

 

[CindyC-IL]

Thanks everyone. I did lock out 7,8,9, and 10 and the mileage was noticeably improved. I'm new to trailering with my truck so will probably improve with experience of what combinations work best.

 

[Xchevyguy]

CindyC, can you quantify what you mean by noticeable? Do you mean around 10% as others have suggested? This thread has really gotten my attention as my truck is used primarily for towing.

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