From time to time, someone will post a thread titled "How many miles do you get from a tank of gas.

So I read through all the replies, and every once a while, someone will post some outrageous claim, and I sit here scratching my head.

Here is the example I will use for you mechanics out there:

Suppose there are 4 trucks, each truck is the same year, approx same mileage, and same configuration
*2002 F150 Supercab
*5.4L
4x4 shortbox

One person claims 12 MPG
Another claims 14 MPG,
Another 13.5 MPG
Then the 4th guy 18.7 MPG

Is it possible all these claims are correct?
It's not like I believe someone would intentionally fib, it's more like I think they are not calculating it properly.

Is it possible to have such a contrast ( 5 MPG difference) on the same trucks, all configured the same way?

The thing is, I know how I take care of my truck, I know how I drive it, and baby it. Change the oil every 2,500 miles, and don't abuse it in the least.

When I see someone say they get 5 or 6 MPG more, I know there isn't anything more I could be doing, so I ask myself "why"?

How is it possible that some of the differences in MPG are so drastic?

Thanks!

 

I don't think there is any particular right answer here. You pretty much nailed all of the points that would make a minute difference in Mpg. If we look at the over all average of mpg we should all be in the same ball park give or take a few miles. I have a 4.6 and when I fill up I average anywhere from 11 mpg-16mpg city driving. My father in his 4.6 gets close to 17mpg on average freeway driving. You also have to take into account the fact that engines are mass produced...I am not an engineer, but we can probably speculate that there will be some slight differences in engine/ drivetrain structure...I don't know. Maybe gas octane or quality plays a role. What about synthetic vs rhinocerous oil?

Interesting inquiry.

 

It's entirely possible. My own mpg varies from a low of 9.9 up to a high of 14 mpg. I always refill the tank the same way and usually from the same pump.

My method of filling up the tank is to lock the nozzle to the maximum and let it knock off automatically. Then I start filling again, but with the trip on the first notch until it knocks off again.

The 9.9 mpg happened at a time when it took me 15 days to burn 13.5 gallons of gas. That means I drove very short trips over a two week period. My best mpg came at a time when I filled up 16 gallons in a 7 day period.

On average, I'm putting in about 16 gallons every 2 weeks and at that rate, I'm getting 10.7 mpg to 13.9 mpg over the last 3 months.

If I can get 14 mpg with my 5.4L SuperCrew 4x4, I'm sure 18 or 19 mpg is entirely possible for somebody driving conservatively on a freeway commute. I drive about 100 miles a week. Some days I only drive about 5 miles mixed with a day or two driving 20 or 25 miles. Somebody driving 50 miles a day on a freeway would get a lot better mileage than me.

 

I don't think there is any correct answer. MPG is so subjective. Many things affect it, and most importantly driving style and conditions. No 2 people drive the same. I am one of the guys getting 16.5-18.5 with a 5.4. I always get pretty good milage for whatever vehicle I'm driving. My commute is 70% highway, and I never drive much over 70mph. If I'm running empty up to the cottage I've seen 19. Let my wife drive and I loose 2mpg......no *****. Put a trailer on and I get 10-15 depending on how I drive.
My 3 year old truck has 80K so it doesn't sit still for very long. Lots of highway driving, and good maint. record.

-jeff b.

 

The more miles in the averaging period the more accurate the number. But also, its more general. For example I keep track of my fuel usage and mileage from day 1. I have a spreadsheet that gives mpg per tank ful, per month, per year and total. Total being current miles on the truck divided by total amount of gas used. The tankful and even monthly numbers can vary as much as 2 or three gallons. But the annual and total numbers are holding within 0.1 to 0.2 mpg steady. My total mileage for the 3.5 years I've owned this baby is just a hair over 15.5.

 

There is also differences in fuels. Last I heard there was something like 37 differnt types of gas in the US.

I live in Houston. We have the reformulated gas (RFG). It has about 20% less energy in it. The oxygenated fuels also have less energy. In my wifes 5.4l S-crew, she usually gets 15 on her 5 mile trip to work. If we fill the truck before we leave on a long drive we et 16. Fill up 100 miles outside of town and we get near 20.

I have always wordered how the epa fuel milage is calculated. Which fuel is used?