My mpg on a 2020 e350 v10 motorhome is only 4 mpg

My mpg on a 2020 e350 v10 motorhome is only 4 mpg Most people get 8, what could be wrong

I’m sorry this is a surprise to you. I was surprised it’s “supposed” to be 8 MPG…

You might give it some time. A 2020 anything hasn’t had enough time to “break in”. Maybe measure fuel economy over several more tanks of gas.

Driving environment and driving style make a tremendous difference.


Have you been on long highway trips? If you like to speed, try driving the speed limit. Higher RPMs will use more gas. Try to keep the RPMs near the lower shift point.

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Hold your hand out the window with the palm facing the wind.
That’s what your big brick is working against.
Going 50 instead of 71 cuts that in half.


How many tanks of gas have you used?

It is still under warranty, if you think the problem is mechanical, take it to Ford for repair. If you find, as I suspect, there is nothing wrong, revise your driving style.


EFI, overdrive trans, lighter materials,
our 78 class A got 7mpg. And had no high tech engine controls
Carved 454 with 511 gears


If 4 mpg is a long-term average, and you’re not driving 80 mph, I think there’s something wrong. Use the warranty.

4 mpg is after 3000 miles that I have owned it the truck is actually a 2019 and has 25,000 miles on it

If your driving habits are sedate, take it back and complain.

And just how are you calculating your fuel economy . . . ?!

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take milage, fill with gas, take milage, subtract, fll with gas, divide by number of gallons.


Assuming you’re actually filling until the nozzle clicks off, it sounds like you’re doing it the right way

You might be amazed how many people have absolutely no idea how to correctly calculate fuel economy

That’s why I asked

What kind of driving are you doing?

What speed are you maintaining?

Don’t subtract. Total miles divided by total gallons.

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How do you think he’s getting total miles? He’s subtracting starting mileage from ending mileage on the odo…

It never ceases to amaze me when people come here with a problem seeking input but are unwilling to invest much if any effort themselves. It’s even more baffling when they do return and answer only one of the questions posed but ignore all others…


I use the trip odometer and reset it every time I fill up. Then I don’t have to keep written record of my miles.

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You have driven 3000 miles?
1 trip? Or a number of trips?
We got same mileage on 200 mile trips vs 1000 mile trips
Filling dual 50 gal tanks is sort of a bummer. Dollar wise.
Doing it on consecutive days is more so.

A guy I used to work with couldn’t fill his dual 50s at one stop. About 15 years ago, the max he could spend for gas was $100, and he couldn’t do a full fill up for that. Sometimes he complained about how much it cost to fuel his Class A RV, mostly he complained about not being able to fill it completely.

Many years ago, I knew a person who bought a Flxible (yes, the spelling is correct) intercity bus and converted it to an RV. The bus was powered by a Buick straight eight engine. He claimed to get 8 mpg.