Taking to shop for MPG issues; what to check?

[jblc]

I'm (yet again) taking my '21 XLT to the dealership, this time for MPG issues. MPG has always been really bad on this vehicle even when new, about 19-20 mpg highway (hand-calculated) at 65 mph and no wind, and stock 2wd. Adding a topper and new tires didn't change mpg.

Without any alteration since i got 19-20, the mpg has been steadily dropping to 17-18 over the past year, but more quickly over the past 6 months.

Is there any specific component I should ask them to check, relating to fuel efficiency?

Details:
(a) full-synthetic oil changes every 3k miles (8k miles total), and
(b) nominally-adjusted tire pressure as seasons change, and
(c) auto start/stop active, and
(d) 87 octane from quality station (California),

This is with gentle driving, mostly highway. I got 27 mpg on my '97 ranger, also with topper, so generally know how to drive efficiently and keep my vehicles optimally set up.


I feel like I've been taking this lemon in every two months since the month I bought it...sigh.
Welcoming any suggestions on this issue!

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[9zero1790]

id be curious if it was a possible transmission issue. possibly a computer issue. lot of variables with mpg math. im thinking the dealer should be able to get all the info from the trucks computer and hopefully be able to get something fixed for you.

 

[RedDakooter05]

Full synthetic, change every 5 to 10k. 3k is way too soon.

How many stations have you been using ro get fuel? Sometimes its hard to find high quality fuel.

 

[OHTREMOR]

I'm (yet again) taking my '21 XLT to the dealership, this time for MPG issues. MPG has always been really bad on this vehicle even when new, about 19-20 mpg highway (hand-calculated) at 65 mph and no wind, and stock 2wd. Adding a topper and new tires didn't change mpg.

Without any alteration since i got 19-20, the mpg has been steadily dropping to 17-18 over the past year, but more quickly over the past 6 months.

Is there any specific component I should ask them to check, relating to fuel efficiency?

Details:
(a) full-synthetic oil changes every 3k miles (8k miles total), and
(b) nominally-adjusted tire pressure as seasons change, and
(c) auto start/stop active, and
(d) 87 octane from quality station (California),

This is with gentle driving, mostly highway. I got 27 mpg on my '97 ranger, also with topper, so generally know how to drive efficiently and keep my vehicles optimally set up.


I feel like I've been taking this lemon in every two months since the month I bought it...sigh.
Welcoming any suggestions on this issue!

My Tremor averages right at 20 in the Winter and 21 in warmer months. My driving is about 70-30 highway to city.
I have seen 23 on long highway trips at moderate speeds no more than 70.
At 28 k miles on the truck it does seem to be doing slightly better this Summer.

Not sure if this helps you but can give you something to compare to. Just remember I have the factory lift and the AT Grabber tires with a hard tonneau cover and Raptor style running boards.

 

[MrBusses]

As a ford dealer tech, the dealer isn't going to do anything about your MPGs Ford does not warranty fuel economy issues. If there is no check engine light on or no other obvious issues there is really nothing else to do. My 19 4x4 gets 20-21 on the dash, manually calculating fill ups its really 19-20.

Run better gas is what I suggest. If you are buying from Wawa, race track those types go some where else. I noticed a difference in my mpgs when getting gas from mobile or shell vs wawa

 

[jflogerzi]

your milage is right on target. Ford won't do anything. I am surprised they even took your truck in just for that....

 

[AzScorpion]

Mpg has been beat to death on here. No two people drive the same and it's going to depend on driving style, conditions, gas etc. My new Tremor has been averaging 23.9 with a best of 26.4 mostly highway driving from picking it up in WA and now while on vacation. I only use premium fuel and try to buy from top tier stations. I suspect I"ll start taking a hit now I'm back home and I'll be driving mostly short distances with the ac blasting.

 

[Grumpaw]

Adding a topper for aerodynamics is offset by the extra weight.
Hand calculating is useless...needs to be done properly via an app, the dash, a Scan Gauge.
Auto start/stop is not really saving much, and is offset by the lots of extra that's put on the starter.
Try using a top-tier midgrade gas. I never use regular...mid-grade for day to day, and premium when I tow.
Your mpg is not any better or worse than my 2021 Ranger 2 wheel drive.
It's an over 2 ton truck, with a turbo....it's getting better mpg than similar weight trucks from a decade ago.
Comparing mpg to a Ranger from 26 years ago is comparing apples to oranges....not relevant
I could compare my Ranger's mpg now, to my F-350 dually from 25 years ago, that got 12 mpg, but it's just not relevant..

 

[Dr3wDrop]

I do not see anything wrong with the MPG. I hover at 19 in the winter and 21 in the summer.

 

[Frenchy]

Have you considered actually putting 91 in the tank? I would do that. Also what is your tire pressure that you are running and what tires do you have?

Put simple I need more information

 

[puckdodger]

That's not far from what I was getting. I was levelled, tuned, and ran 91. And I do all the things a guy who tries to maximize his mpg does. Good gas can make a difference on its own, IMO.

 

[airline tech]

There are many variables that affect fuel economy, and if it is not providing any drivability issues or generating any codes. Then the first PID's to check are the Fuel Trims (STFT & LTFT)
The main goal of the fuel trims is to get the LTFT adjusted to near (0) as possible.
The STFT & LTFT (added together) should total to (10) or lower (on a normal running engine)
If you are seeing consistent (+) LTFT above 10, then the PCM is adding fuel to compensate for a lean condition.
Top things to check for this are: O2 Sensor, Vac Leak, Clogged Fuel Injectors and if it has doing this for a long period of time - Plugged Cat Convertor
Hopefully it has coded something, so you have a direction to look at.
The most common would most likely be a lazy O2 Sensor, but its hard to tell without checking the Fuel Trims and branch out from there.

 

[Canadian Ranger]

Motor oil isn't going to effect gas mileage too dramatically in today's vehicles. A good oil, filter and routine drain intervals helps with engine longevity and cleanliness. The computers are too finely tuned. Change to a good oil in an older vehicle, and you'll see & hear the difference just starting the car in your driveway.
Have you changed all of your driveline fluids? I noticed an MPG improvement, and power improvement after changing mine.
Also, I've discovered that calculating mileage over the distance of two tanks of gas gives better accuracy. As does using cruse control when you can, but avoid using the "+" when accelerating with the cruise control on. It's too abrupt and you want to slowly increase your speed.

 

[FunInTheSun]

Mpg has been beat to death on here. No two people drive the same and it's going to depend on driving style, conditions, gas etc. My new Tremor has been averaging 23.9 with a best of 26.4 mostly highway driving from picking it up in WA and now while on vacation. I only use premium fuel and try to buy from top tier stations. I suspect I"ll start taking a hit now I'm back home and I'll be driving mostly short distances with the ac blasting.

100% on this. It's hard to even talk about it because no one agrees on what number to even use. Some people with amazing numbers will be (come to find out) quoting their on-the-fly estimate of the bouncing ball numbers when they are on the highway at speed. Others will be giving you the number the truck gives you on the trip computer display. Others will give you the hand-calculated figures. So take everything people SAY with a grain of salt. They may not mean what you think they mean. So keep the flame throwers on standby...

Real world mpg figures are heavily affected by driving style. Some people swear by driving slow everywhere. But what is the max mpg you can get in a low gear? Not good. Highway driving gets you into a higher gear ratio, which is good, but the exponential air resistance curve limits how much you can get out of that game. Stop and go driving takes a terrible toll, because how many mpg are you getting when you are sitting still? ZERO. And accelerating a heavier vehicle costs you more than a lighter vehicle... No matter what, stop and go driving forces you to give a squeeze on the loud pedal to get her going again, and that takes a toll, too. Jury is still out on exacty how hard to squeeze the lemon to get the optimal result there, because you want to spend less time in the lower gear, but WOT is wasting fuel, too. So balancing act there, without a lot of data to go by. Some people imagine a lemon under the gas pedal foot. OK to mash it, but do it ... smoothly ... and not too hard ... I do a lot of city driving in my Ranger, and my dash computer shows 14.2 MPG average. That may seem shocking, but I spend a lot of time idling with the AC on. (It's Florida, folks... My Auto Start Stop system has not kicked the truck off for months now. Outside air temperatures come into play in that algorithm...) Some of that is just sitting at traffic lights, and some of it is sitting in parking lots waiting for someone else to finish an errand.

Bottom line, there is a price to pay for power and capability, and it's like feeding the body. You want a power lifter physique, you are going to eat like a power lifter. Same for vehicles. If I didn't need the capability, I wouldn't pay for it. Since it does what I need it to do, it's just the cost of doing business.

 

[JasonTremor]

You noted California. Have they switched from selling E10 to E15 ethanol content fuel recently? Your MPG will drop with E15.

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