Why is my MPG so "poor"?

[AzScorpion]

I drive the speed limit, use cruise, use ASS, fill with 87 octane, rarely use sport mode, never
used towing, truck is stock. Wife uses it most of the time cuz I WFH. So by far most tanks
are 50/50 driving. Best tank was on a trip up past Quebec city where it's hilly, used
sport mode, close to 23.5 mpg. Here is my milage per tank:
Hand calculated - "liters/km=l/100km mth/day (computer)"

10 liters = 23 mpg
11 liters=21.4 mpg
12 liters=19.6 mpg
13 liters=18mpg

Truck is rated at 9.8 / 10.8 / 11.8 hwy/city/combined

I was not impressed the first few months.... now at 10k miles.

You should download the Fuelly app on your phone. It calculates all this for you and stores your service records too. Much easier than making notes every time you fill up.

https://www.fuelly.com

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[jsphlynch]

Do the opposite and syphon it out and watch his reaction. This way you're not spending money on gas and using his to fill your tank all while watching him freak out. ?

Or syphon out some times, put it back in on others. Watch him scratch his head over how insanely variable his MPGs are.

 

[Dunedain Ranger]

I'm completely stock on my 2WD XL - I don't tow, haul stuff(yet), or go off-road.
I consistently run 93 Shell and average about 24-26 mpg, except for the days when I'm listening to songs, like, oh I don't know, "Vaseline" by the Stone Temple Pilots, or "Goodbye Stranger" by Supertramp, "Foreplay" by Boston and really nail it when the lead guitar kicks in - then indubitably there is a dramatic decrease in mpg - but hey, those are great hauling a** songs, amongst others...

 

[CB750F]

You should download the Fuelly app on your phone. It calculates all this for you and stores your service records too. Much easier than making notes every time you fill up.

https://www.fuelly.com

Easier, freak that, I'm old school, I'll be stopping this anyway.
I adjusted the thingy to track better/close to 'real' numbers. As soon as it's
close enough I'll just be checking what the truck says every fill up...
I really only keep track & see if it changes/something wrong.

 

[NetRedding]

i own a 2021 XL FX4 stock EXCEPT i put on cooper discoverer at-4s tires. same exact size as stock. They do weigh 5lbs more per tire than stock. I have 6500 miles. It seems on a long road trip of 200 miles, the best i can get is 23 mpg. This is going 55-70mph and most of those miles 67 mph. Very little stop and go. I do not use the auto start/stop feature. This same route i'd get 21mpg with my xterra with oversized tires and a tune. it was rated 16/21 mpg. I would see 23mpg with it back with stock tires. My patriot, rated at 22/25mpg saw consistent 26.4 on the same trip. And it had heavier tires- by 2 lbs a tire.

i keep seeing people saying on fakevook that they see 29mpg on highway, fx4. Lots of 27mpgs...... Does the 5lbs per tire really eat up 4mpg?

my oil level does rise- fuel in oil- but it's halfway between the high hash and top dot when cold, right below top dot when hot. I can't see that causing my poor mpgs....

i intentionally went with the coopers for their better winter driving characteristics as i go thru mountains alot. and they seem more rugged as far as sidewalls go.

i would expect though to see that 24 or 25mpg when i nurse it on the flat roads...... thoughts?

I get the same mileage in my 2019 Lariet FX4. Displayed mpg is always 1-2 mpg better than actual.

 

[Groo]

Groo here
My 2020 STX 4dr With FX4 Tow package And stock all around. [and 87]
Last trip to get parts for BIL .
Temp 55, empty up , 1000lb in bed, back [about 100lb under max]]
cruse at 55 when possible air on [to keep glass clear] trans in "D"
Ohio state route in country [rolling hills] and towns ..
26 and a touch going up 25 back round trip 150 miles.[do this about every 2/3 weeks just different weights]
Tried D to see worst case lugging of engine [down to 1300 or so]
Just shifts more and goes to top gear faster.
Looks like air resistance plays much more than weight.
Probable with trailers also.
Ps most drop measured is 2 1/2 inch at hitch

 

[tigeraces]

i own a 2021 XL FX4 stock EXCEPT i put on cooper discoverer at-4s tires. same exact size as stock. They do weigh 5lbs more per tire than stock. I have 6500 miles. It seems on a long road trip of 200 miles, the best i can get is 23 mpg. This is going 55-70mph and most of those miles 67 mph. Very little stop and go. I do not use the auto start/stop feature. This same route i'd get 21mpg with my xterra with oversized tires and a tune. it was rated 16/21 mpg. I would see 23mpg with it back with stock tires. My patriot, rated at 22/25mpg saw consistent 26.4 on the same trip. And it had heavier tires- by 2 lbs a tire.

i keep seeing people saying on fakevook that they see 29mpg on highway, fx4. Lots of 27mpgs...... Does the 5lbs per tire really eat up 4mpg?

my oil level does rise- fuel in oil- but it's halfway between the high hash and top dot when cold, right below top dot when hot. I can't see that causing my poor mpgs....

i intentionally went with the coopers for their better winter driving characteristics as i go thru mountains alot. and they seem more rugged as far as sidewalls go.

i would expect though to see that 24 or 25mpg when i nurse it on the flat roads...... thoughts?

That is actually great mpg. I have no idea what's killing my mpg. All stock fx4

 

[OstAgain]

Hello world.
I have a stock '21 XLT Supercab and get around 17.75mpg on 87 octane, and about 19mpg on 91 octane.
I've swapped tanks of fuel between the two for about 4 months now with the same results.
So for me having done the math (cost per mile) & for general city driving the extra cost of 91 octane is not worth it.
Also, the truck always seems to read 1~2mpg better than actual math shows!
Stay groovy people.

 

[MinuteMan]

right, i try light foot. sometimes though it's chugging and a heavier foot is needed to downshift in drive. but that doesn't seem to happen to me once i hit the four lanes. and i fill up right at the start of the 4 lanes. so i am driving lightly, like my other vehicles coming back. now in the mountains, no, i use sport mode alot and enjoy it.

don't get me wrong, i love the truck. jsut trying to see if what i am seeing is normal- with people reporting 26/27++ mpgs on highway makes me think it's not- or if i have some sort of problem, albeit minor...

perhaps ford is more "accurate" with their mpgs claims and the other brands i have had took a more conservative approach- you know- the whole under promise so over deliver...

There are a few folks who have tunes, adjusted speedos for bigger tires and air filters and exhaust systems. It’s hard to compete with that.

Pro tip: don’t let your wife drive it.

My wife is either on the brake or on the gas, no coasting. She can’t understand why she gets poor mileage and her brakes make noise.

 

[MinuteMan]

I beg to differ, see my post #12.

My last fill up was 24.3 and I drive 70-75, if you drive any slower here you'll be run off the highway. Mine is leveled, larger tires and tuned. My lifetime average is 22 but there's so many variables between the way everyone drives it's impossible to get an exact average that everyone should have.

I know. I’m jealous. I’d like to get my tune and speedo adjusted but I bought a retirement home last year and I’ve been spending every extra penny getting it ready. I’m not whining, just redirecting funds. I really wanted the superchips flashpaq for the speedo recalibration and the throttle adjustment. Any included tunes were going to be a bonus. I did dive into the deep end of research regarding all of the tunes and companies that were recommended and my top choice was Livernois. I would 100% use the economy tune 98% of the time…….of course.

 

[AzScorpion]

I know. I’m jealous. I’d like to get my tune and speedo adjusted but I bought a retirement home last year and I’ve been spending every extra penny getting it ready. I’m not whining, just redirecting funds. I really wanted the superchips flashpaq for the speedo recalibration and the throttle adjustment. Any included tunes were going to be a bonus. I did dive into the deep end of research regarding all of the tunes and companies that were recommended and my top choice was Livernois. I would 100% use the economy tune 98% of the time…….of course.

I don't blame you, I'd sink the money into the house now as it'll payoff later. You can always tune it and who knows maybe there will be a special ($100/off) like before. Plus with the Livernois tune you can adjust for tires size which will recalibrate your speedo. It's easy to do and here's a post on where to start if you go up to 265/70/17. I did it and it's perfect now. Good luck with the house!


https://www.ranger5g.com/forum/threads/livernois-tuning-released.2036/page-16#post-139464

 

[Langwilliams]

I'm thinking about not correcting my speedometer after installing 265/70/17's. I have a speedometer app on the phone an it shows about 1 mph off under 40 an about 2 or at 70 mph.

Tire size calculator says there's a 5% difference. If I add 5% to the shown speed I get what the app shows.

So I guess I can add 5% to the MPGs?

 

[MinuteMan]

I'm thinking about not correcting my speedometer after installing 265/70/17's. I have a speedometer app on the phone an it shows about 1 mph off under 40 an about 2 or at 70 mph.

Tire size calculator says there's a 5% difference. If I add 5% to the shown speed I get what the app shows.

So I guess I can add 5% to the MPGs?

You just made my brain explode. 5% difference in tire size and 5% increase in shown mph equals 5% increase In mpg. Hmmmmmm. Oh… No, I uh…. I almost had it and lost it again. Mmmmmmmmm. I’m Homer Simpson right now. Mmmmmmmmm.

 

[got3fords]

I have noticed a definite drop lately. I used to get mid 20's when it was pretty new. If I filled up on the way to work, by the time I got across and parked it would be in the upper 20's. Now I am lucky to see 23, and the cross town trip after filling up gets me only about 23 as well. Nothing is different except maybe winter fuel blend.

 

[AzScorpion]

I have noticed a definite drop lately. I used to get mid 20's when it was pretty new. If I filled up on the way to work, by the time I got across and parked it would be in the upper 20's. Now I am lucky to see 23, and the cross town trip after filling up gets me only about 23 as well. Nothing is different except maybe winter fuel blend.

It's most likely the winter blend plus it's colder out and idling a little more. I notice mine goes down too (1-2 mpg) once it gets colder out here and idling kills the mileage. Watch your gauge as it's warming up and you'll see the mpg ticking down.

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