2021 Trail Boss Gas Mileage Issues

[Slyzon23]

Less than 2000 miles on the my truck and when I fill the tank the computer is showing 290 miles to the tank. I am only averaging 12 mpg according to the computer on city driving. I have several friends and co workers that have the exact same truck that is getting 460-480 to the tank according to their computers. I have taken it back to the dealer and I was told there is no error codes therefore there is nothing they can do. I was told to keep driving it and it will probably get better with time. I have contacted the home officer and I was told there is nothing they can do because they rely on their certified dealerships and service centers to diagnose any issues. I am considering returning it or selling it back to them. I will lose about 4k in the sell back but might be worth it with the gas mileage I am currently getting.

 

[Grit dog]

Dude, before freaking out. Check your speed against a gps to make sure the speedo/odometer is correct.
Then fill up, run a whole tank of gas and hand calc the mileage.
The numbers your co workers are seeing seem fairly optimistic, plus miles to empty is an algorithm based off of current mpg (you can see it fluctuate a bunch depending how your driving it, fairly real time).
Trading in a new truck because the mileage is a little low is about the silliest thing I've heard.
FWIW, my avg per the computer over 20k miles is in the 14s.
You have under 2k miles of farting around. Engine hasn't even loosened up yet and nothing is even broke in.

 

[Frombieman]

Curious. 6.2 or 5.3 engine.

 

[Slyzon23]

Curious. 6.2 or 5.3 engine.

5.3 10 speed

Curious. 6.2 or 5.3 engine.

 

[Jmzvet]

Give it some time. So many variables factor into fuel mileage. The biggest one Ive noticed is highway vs street driving.
Can be a 10 mpg difference.

 

[Jmac49]

My 21 Trailboss 6.2L has 12k?+ miles...overall average 18.3mpg. On road trips will get 20.5 to 21mpg on reasonably flat highway at 70mph ish.
So I would give the issue some time, although mine was good from the get go.

 

[Fireman489]

5.3 L 10 spd. I'm 50/50 city/hwy. I drive conservatively without getting passed by grandma and I Calculate my mpg with the simply auto app.

 

[bowtie383]

I didn't buy mine for MPG. I only have 500 miles so not sure yet

 

[wesg79]

still not broke in and every truck, even the 4.3 or a mid size truck has garbage MPG around town, only time your going to see good MPG numbers on the computer is a long highway drive to get that average up and push the old city driving numbers out of the calculations and have the engine up to operating temp

my 6.2 is terrible in town and i have DFM disabled and auto stop start but when i drive 2 miles to work each way the engine isnt even up to temp so the computer numbers are horrendous, if i get on the highway and set my cruise and reset the fuel economy its does quite well. as bad as my city MPG is i can drive around 2 weeks before my needle even comes off the full mark if its just in town

 

[Elk Hunter]

Less than 2000 miles on the my truck and when I fill the tank the computer is showing 290 miles to the tank. I am only averaging 12 mpg according to the computer on city driving. I have several friends and co workers that have the exact same truck that is getting 460-480 to the tank according to their computers. I have taken it back to the dealer and I was told there is no error codes therefore there is nothing they can do. I was told to keep driving it and it will probably get better with time. I have contacted the home officer and I was told there is nothing they can do because they rely on their certified dealerships and service centers to diagnose any issues. I am considering returning it or selling it back to them. I will lose about 4k in the sell back but might be worth it with the gas mileage I am currently getting.

Let the engine break in. Do a manual MPG check on a full tank of gas. Set your mode to normal not sport as sport raises your engine rpm. Then compare your manual check to the computer. Mine is within .2-.4 mpg from a manual check. City driving is going to be low mines 15-16 mpg. Freeway runs 17.2-19.8 depending on speed which is usually about 75+ for me, it would be 19-20 if I ran 70mph. I'm running a 5.3 with the 10 speed. But like everyone is telling you that engine is still new and tight. Mine has 15K+ on it.