Fuel Mileage - Display versus Calculated?

[BruceAZ]

I searched and did not find a thread on this topic and read a few threads on how to get the best mileage, but not this topic. Just took delivery of my 4-dr with 2.3, but the question is applicable to all models I think.
For those of you who have calculated your mileage the old fashion way - divide miles traveled by gallons burned by hand, how much difference do you see between what mileage is actually attained versus what the Bronco display show? I suspect the display is generous (to put it tactfully). My Dodge PU with Cummins diesel gets about 20 mpg, but on every tank the display lies by a mile or so per gallon. For instance, if the display shows an average of 20.5, the calculated mileage is more like 19.5.
Thanks for any real world experiences.

Sponsored

 

[rblock50]

Oh yeah, its called a Lie-O-Meter for sure. The last time I manually calculated it, I think I was about 16.2 on the dash, but doing it by hand was about 14.25, so that time it was about ~12% off for me, but YMMV of course (literally lol).

 

[mcinfantry]

I’ve manually calculated every single gallon on every car I’ve owned for over a decade

 

[RagnarKon]

I admittedly have zero idea what the computer tells me because I don't even look at it.

But I do calculate from fuel receipts:

And just for fun... here is my Focus:

 

[GatorFord]

I use Fuelly and the calculated mileage is usually within 1 mpg. Probably about 0.5-0.6 on average. Below is a screen capture of what Fuelly says my average mileage is since I bought the truck. It's much better now that it's broken in (13k miles) and the JB4 tuner. I run premium.

 

[Butzy]

I'm consistently off by 2mpg. FYI it's not my math. Oh by the way, there are some very smart individuals in here who will tell you that your calculations are completely off because of temperature change and btus. Just know it's probably coming. Oh and it's a brick and we shouldn't care. That's also coming......

 

[atlawson]

I'm normally off about .. 75 to 1 mpg with each tank. It has gotten close though when I put larger tires on.

 

[BostonSasquatch]

I'll send up an "amen" to GatorFord's post (above) and add my endorsement to the Fuelio app. Gives you current (previous tankful) and cumulative mileage. It's accuracy is well within the margin of error.

It also computes your cost per mile, which is instructive and, to me, quite sobering. When you see that you're spending $.19-.21/mile, you think about how much each drive is. That trip down to Home Depot costs me $2.20--Hmmm...maybe I'll postpone it till I have other errands in the area. Overshooting that exit--the next exit is 10 miles, plus the clover leafs? That cost me about $5.00! Gotta pay better attention!

 

[RedDawg]

My lying computer gives me an extra mile.

 

[kodiakisland]

I’ve manually calculated every single gallon on every car I’ve owned for over a decade

You need a more interesting hobby.

 

[contented]

I’m similar to others, dash display overstates by 1.2 to 1.7 mpg. I’ve just resigned myself to the fact that it’s a gas hog. Haven’t owned a car yet where displayed mpg was consistently close to accurate.

 

[JT58Bronc]

My Bronco MPG meter is pretty accurate, I get .5-1 mpg better than what it shows.

I have to say averaging almost 23 MPG is my 2 door Sas is pretty amazing for the vehicle being a brick in the wind. I have a 2023 GTI that does not seem to get good MPG for what it is. I know comparing the GTI to the Bronco is irrelevant but the Bronco coasts better and I am off the gas a lot. The GTI I does not coast as good and I have to keep it on the gas longer when coming to lights. It's got to be the high RPM in the GTI. Bronco idles along like 1200-1500 RPM, GTI is always doing 2000-2500 even at only 50 MPH and 3000 at 70. So, impressed with the Bronco not with the GTI.

 

[MrParticular]

I'm getting waaay better mileage than the sticker. And I didn't buy it to save gas.

 

[JL8jeff]

I have just over 1300 miles on my 2.7 base SAS so far in the last 4 months (I mainly do local driving under 50 mph so not a lot of miles) and the computer mpg generally runs about .3 to .4 mpg above my calculated mpg. If I don't have the tank stuffed, it reads a little lower but will average right back out with the next fill up. As of my last fill up, my calculated mpg is 17.036 and the computer has 17.3 so pretty close. I just did a beach run Sunday and it jumped to 21 mpg on this tank on the computer, so the overall is going up with the next fill up.

 

[Big Boss]

display for me is constantly optimistic by about 1.5 to 2.5 MPG

Sponsored