F-250 Towing Mileage Reduced by 25%

[rklavoon]

I took my 2015 F-250 4x4 6.2L V8 and trailer out for the first time this year. Truck has 15,200 miles on it and it is due for an oil change and tire rotation (right at the 5,000 mile mark). No check engine lights on at all.

Gas mileage last year was 8-9 MPG towing 7500# (loaded) Jayco 29QBH.

On this trip I averaged 6.2 MPG. (Hand calculated)

Only things different from this year to last year:
* Filled 1 30 lb propane cylinder
* Trucks tires have 65 psi pressure in them compared to 60 psi last year.
* I changed the air filter in the truck 2 weeks ago.

I am looking for some ideas/thoughts on why my mileage has dropped so much.

I understand that there are a number of factors such as wind, etc, but this just doesn't feel right and the truck seems to lack some power.

TIA!!!

[Slowmover]

60-mph is the wall. Any vehicle.

[danrclem]

I just got back from a 1st trip with my 2011 6.2 pulling a 7640# dry weight 5th wheel. I'm not really sure how much extra weight I loaded into it but the water tank was empty.

I-64 from Louisville, Ky. area to south I-75 (almost to Tn.) through some pretty decent but not huge hills running 65 to 66 mph. On the way down the meter showed 8.7 mpg and after I filled up it hand calculated 8.56 mpg. The gas was cheap so I probably shoved an extra 1/2 gallon in the tank so actual mileage may have been a bit better.

On the way back I decided to slow down some to about 63 mph and the meter was showing 9.9 mpg and hit 10 mpg in a few places. We stoped to eat and I decided to slow it down a bit more to about 61 mph and ran that speed all the way home until I got off of the interstate. Even though the hills were smaller after I dropped the speed the complete trip dropped to 9.7 mpg. It looks like 63 mpg may be my sweet spot but I'll experiment a bit more just to make sure. I haven't filled up yet to calculate the real world mileage on the return trip but I'm guessing the meter is not too far off.

[hellfirehydra]

Wind is everything when towing. 5mph headwind vs 5mph tailwind can easily change MPG by a significant amount.

[JBarca]

rklavoon wrote:
Update: Mileage seems to have "normalized". I either got a bad tank of gas, or the stations were still using Winter blend fuel in April.

I went Buffalo to Monroe Michigan and got 7.9 MPG and then back (tailwind) and got 8.5. This is closer to what I have been seeing.

I met a guy at the campground that that the exact same truck and trailer as me, same size family, etc and he was getting 11.5 MPG towing 8,000 lbs (6.2L gas engine).....not sure how he was accomplishing that.

Your 6.2 is newer then my 6.8 V10, but the gas deal is a real big factor. Mine does not like ethanol in any amount. Back when I use to be able to get real gas, WOW the mpg jumped with just the tank fill up. And stayed that way until it went back to the ethanol blend. The first tank of blend after get real gas and the MPG started going back down. You could watch the towing MPG start going down in just one tank. Summer winter blend is a factor too.

Your 6.2 mileage is a little higher then mine but not much. Pulling 10,000# of TT, I get 7.5 to 8.0 towing 55 to 60mph. If I do a lot of hills, it is more in the 7.0 to 7.5 range. The only time I was able to get up into the 9.0 to 9.5 was on real gas. And around here in OH, marinas are about the only places left you can get real gas.

Now how that guy you talked to gets 11.5mpg gallons towing 8,000# of TT,..... did he happen to say how many fuel tanks worth he was able to do this for and what speed to tows at? Is he using real gas or an ethanol blend? This 8 foot wide brick we tow, eats fuel. Weight is not as much a factor as wind drag and towing speed.

I must say, I do like my 3 valve V10. It is one good towing engine, nice flat torque curve at lower RPM's then the newer higher speed engines, just she has a drink'in problem...

Sounds like buying new 6.2 gasser is not going to really help on the mpg that much. I'll keep mine a little longer right now unless gas prices go really nuts again and stays that way. I just turned 103,000 on the odometer.

Thanks

John

[Bobbo]

Were you going faster? On my previous MH, at 60 mph I got 9 mpg, at 70 mph I got 6 mpg.

[rklavoon]

Update: Mileage seems to have "normalized". I either got a bad tank of gas, or the stations were still using Winter blend fuel in April.

I went Buffalo to Monroe Michigan and got 7.9 MPG and then back (tailwind) and got 8.5. This is closer to what I have been seeing.

I met a guy at the campground that that the exact same truck and trailer as me, same size family, etc and he was getting 11.5 MPG towing 8,000 lbs (6.2L gas engine).....not sure how he was accomplishing that.

[IHnutz]

BenK wrote:
Check when your area switches from Winter blend to Summer Blend fuel...

Always see a difference in MPG and during the switch, the computer has to re-learn HOW2 manage it

Main thing is: RVP, or Reid Vapor Pressure and alcohol content also varies from state to state, region to region and city to city

X2

[BenK]

Check when your area switches from Winter blend to Summer Blend fuel...

Always see a difference in MPG and during the switch, the computer has to re-learn HOW2 manage it

Main thing is: RVP, or Reid Vapor Pressure and alcohol content also varies from state to state, region to region and city to city

[Slowmover]

On both vehicles:

Alignment
Brake drag
Tire pressure

On TT:

Bearing preset

On TV

Fuel & Air Delivery

On lash up:

Set WDH at CAT Scale. Obtain good numbers using three pass method. Use this as baseline. I've seen changes of 20% after rectifying.

As to testing:

Use crruise control for consistency. Avoid lane changing, and keep speed below 64. Commercial traffic moves at this speed and higher. Don't mix with commercial traffic or today's ultra-idiot four wheelers.

Be very consistent trip to trip.

[dodge_guy]

Were you traveling west? That always kills mileage due to the wind. Whenever I head west my mileage suffers on my way home it improves. Also were you still running winter blend fuel? That will impact mileage. Lots of variables.

[RedRocket204]

A dirty air filter can greatly impact your available power and make a truck/car feel "not right". Add in different environmentals and there you go.

[Lantley]

Hard to conclude anything from just 1 trip. As mentioned it could be just wind.Take a few more trips before you make any judgements

[Lwiddis]

One trip comparison? Do two or three more but is mileage ok not towing?

[DutchmenSport]

Variations could be caused by wind resistance. If you were driving directly into a strong wind, your mileage will drop. A strong tail wind, your mileage improves.

Another factor is hills. Were you driving flat land vs hills or mountains. And the next factor is how many times you came to a complete stop and had to start moving forward again. Every start from a dead stop (like stop lights) absolutely kills fuel mileage ..... ESPECIALLY when towing. So if you did a lot of towing in a town or city environment, that will absolutely tear up your mileage.