Got my EcoBoost last April and was averaging around 19-20 mpg.
I put on a 2.5” level and 35” Trail Grapplers, and now I can’t get over 13 mpg. I run my tires at around 32 psi—could that be a factor? Or is it just the weight and resistance from the bigger tires?
Any advice would help!
First off… it’s winter.
Second… what did you expect?
Jin said:
First off… it’s winter.
Second… what did you expect?
Lol, the mid-80s weather in the South would like a word with you.
A 2.5” level with 35” tires adds extra unsprung weight and rolling resistance, so yeah, your mpg is going to take a hit. Plus, the larger tires increase your rotations per mile, which can throw off your dash readings.
What’s your axle ratio? You might want to look up a tire size comparison to your stock setup and use FORScan to adjust your speedometer readings.
If you can’t do that, try hand-calculating your mpg to see how far off your dash is.
@Vail
Wouldn’t 2.5’ actually be 2’6” though? Lol
Technically, yeah! But Ford does weird things with measurements… like their 5.5-foot truck beds that are actually 5’5”.
@Vail
Now I’m wondering… do they mean 5 feet 5 inches or 5.5 feet (which is actually 5 feet 6 inches)? If they shorted us an inch, that’s false advertising!
@Vail
This is the right answer. Reprogram your ECM with FORScan to correct for the new tire size, or go for an SCT Livewire programmer—it’s easier to use and saves your stock settings. That way, when you swap back to stock wheels before selling the truck, you can reset it easily.
FORScan is cheap and works great if you don’t mind a little DIY.
I have a 2018 3.5 with 33”s and a 2” level, plus a Leer cap on a 5.5’ bed. Still averaging 17-18 mpg, and around 20 on the highway.
You made the truck less aerodynamic and added a lot more rotating mass. No way your mpg was going to stay the same. Try running your tires closer to max PSI.
You did the classic mpg-killing mods, so yeah, that drop is normal.
You can adjust your speedometer to compensate for the oversized tires, but lifting the truck increased aerodynamic drag, and the bigger wheels/tires add weight and rolling resistance. It’s just physics.
My 2021 3.5 Lariat gets 18-20 mpg. Closer to 18 in the winter.
Zero mods.
I have the same mods on my 2020 3.5 and I’m getting around 17-18 mpg.
My brother’s 2017 3.5 EcoBoost gets 12 mpg with a 6-inch lift and 35s. All-terrain tires.
You added a ton of weight to your wheels and tires, so that takes extra energy to keep turning.
My ‘19 EcoBoost is stock and can go over 750 miles on a full 36-gallon tank on the highway.
Adler said:
You added a ton of weight to your wheels and tires, so that takes extra energy to keep turning.
My ‘19 EcoBoost is stock and can go over 750 miles on a full 36-gallon tank on the highway.
Damn, I wish I had the 36-gallon tank.
@Poe
King Ranch and Platinum trims come with it. Not sure about others.
Might be worth checking your MAP/MAF sensors—there are three of them, and they could be dirty. What’s your odometer reading? Could be time for new spark plugs (they’re due around 60k miles). Also, check your air filter.
Lots of little things factor into mpg. My truck usually shows lower mpg because my daily drive is only 8 miles round trip. Short trips really kill fuel economy.