Fuel economy with the 6.2

[jakrbt]

Is the premium fuel "required" new to the refresh? I have a '21 6.2 and it just says recommended, same as the wife's Acura, my coworker's F150, and seemingly every other newer car/truck in the past 5 years. I'm at 50k and run 87 octane 90% of the time. The other 10% is 89.

On the 50mi average I'm at 13.8 and best is 30.2. That is with DFM disabled and 60lb load E tires.

I had a ‘21 w/ a 6.2L and for the first few months ran 87. But I started noticing a ticking sound at idle and after doing some research discovered it was predetonation caused from rubbing low octane fuel in a high compression engine. Switched to 93 octane and never heard it again. My nearly 3 week old ‘24 AT4X 6.2L has been filled with premium since it left the dealership. I’m sure they didn’t fill it with premium but I won’t use anything but now

 

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[20AT421]

I had a ‘21 w/ a 6.2L and for the first few months ran 87. But I started noticing a ticking sound at idle and after doing some research discovered it was predetonation caused from rubbing low octane fuel in a high compression engine. Switched to 93 octane and never heard it again. My nearly 3 week old ‘24 AT4X 6.2L has been filled with premium since it left the dealership. I’m sure they didn’t fill it with premium but I won’t use anything but now

I had a '17 Sierra Denali with the 6.2 before this one. It had the ticks (more like marbles in a coffee can on acceleration) and I read about the fuel thing, so I ran 93 for the next year. Never made a difference. I talked to some tuning shops that have tuned them and require 93, but they said that the GM factory tune on the engine isn't turned up enough to require the higher octane (at least in their opinion) so I save my money. 3 years and no tick in the '21 yet

 

[pigpen23]

I realize it's not an AT4 but my Silverado RST with the 6.2L has averaged 14.7 MPG over 47k miles and I'd say I've got a lead foot. Always run premium gas and full synthetic Mobil 1 oil. Predominantly driven highway miles with quite a bit of idling and towing mixed in there. The best mileage I've seen is 19.2 on the day I drove it home when it was stock lol. I'm leveled with 35s. Love the power, hate the short range due to the size of the tank. More than likely switching to the 3.0 baby Dmax with the new truck in May.

 

[Highlander]

Dang! I can't believe the gas mileage y'all are saying. I am getting on average 22mpg. I have a '21 AT4 with the same 6.2L. It goes to about 11mpg when towing my 30ft RV. Most of my driving is in town. I do try and keep my foot out of the accelerator and have the habit of turning off that annoying auto stop every time I get behind the wheel. The only things I've done to the truck are an S&B cold air intake and a J&L oil catch can. Still stock everywhere else. No problems except the navigation won't recognize the SD card but I always use my Google maps with my phone so that isn't a real issue.

 

[Leo581]

I'm averaging 14 around town and can get up to 19 on the highway, in sport mode.

 

[myrez]

I'm averaging 14 around town and can get up to 19 on the highway, in sport mode.

Sounds about right.

 

[whAT4]

My '19 SLT with the 6.2 averaged 20.2 mpg over the time I owned it, and that includes pulling an 18' enclosed trailer some. My first trip with the '24 AT4 I got around 15 mpg, but as the weather has warmed and it's broken in I frequently see 19.x . My trip to work this morning (half city, half hwy) was 19.9. My avg so far is up to 18.4.

 

[DaveW]

Sorry if this has been brought up before but this is my first 6.2. I have around 2200 miles on it now and gotta say I love everything about the truck except the fuel economy. My first long trip I took was around 260 miles round trip and most of it was highway (75mph). Ended up with around 15 mpg average. Since then I havent seen that again. Around 1500 miles I installed a 1.75" leveling kit and 275/60-20 tires and wheels. Now I expected to see a slight drop in economy but damn I am lucky to see 13 mpg's now if I baby it. I am not ooking forward to what it will be when I pull my 7x16 enclosed trailer. What are the rest of you guys seeing?

I have a 2021 Sierra AT4 and just recently installed a Pulsar LT module to disable DFM. Fortunately it has other fun functions of changing gear ratios. Stock diff ratio is 3.42:1, I dropped it to a 3.23:1 and now roll 1500 RPM at 70MPH. I could take the ratio lower as the module allows a setting of 2:1 all the way to 5.99:1. Ive already seen a positive change in MPG just know you’ll lose some low end torque in favor of lingeo legs on the highway.

 

[gemarsh]

I have a 2021 Sierra AT4 and just recently installed a Pulsar LT module to disable DFM. Fortunately it has other fun functions of changing gear ratios. Stock diff ratio is 3.42:1, I dropped it to a 3.23:1 and now roll 1500 RPM at 70MPH. I could take the ratio lower as the module allows a setting of 2:1 all the way to 5.99:1. Ive already seen a positive change in MPG just know you’ll lose some low end torque in favor of lingeo legs on the highway.

Welcome.

 

[Chalkdaddy87]

Here is what I have from my dash...

25mi avg
Best - 22.3
Avg - 18.0

50mi avg
Best - 20.3
Avg - 18.6

450 avg
Best - 16.9
Avg - 15.8


Alltime...

14.6 mpg over 9101.1 miles but an average speed of 27.4 mph because I work in my truck while my daughter is at soccer practice so there's a lot of time idling.

Highway I seem to get a sweet spot at about 70mph, but I can't make myself drive that slow.

My 2019 6.2L is pretty much spot on with yours. Mine is leveled, 35x12.5x20 KO2's, S&B Cold Air intake, and Pulsar LT with AFM/DFM disabled.

 

[gemarsh]

My 2019 6.2L is pretty much spot on with yours. Mine is leveled, 35x12.5x20 KO2's, S&B Cold Air intake, and Pulsar LT with AFM/DFM disabled.

Welcome.

 

[MarkGuaragna]

Hey fellas. I have a 2022 at4 6.2l coming from a 2015 ram 1500 5.7l . As I do with all my trucks I put 305/55-20 on them . I’m running nitto420 and love the look and the ride. I live in upstate ny, and with the mountainous terrain , even highway is shitty with about 15mpg avg. but I took this truck to NC 900mi away for my first trip and got avg 21 mpg ! I was impressed and maintained 20mpg for the ride home. Recently I just went to Boston mass, (all highway) and got 20mpg again. Driving habits are huge and I love to hear my exhaust but my wallet deters me. Lol. These trucks do great mpg on highway and flat land , once u hit the mountains or pull expect the expected .

Hey there, how did you get the 305/55/20 ‘s to work on the at4
I got my rims from my old truck through them on.
Rubbing in the back of the wheel well.
What did you do to make them fit?

 

[Don S]

In combined driving with the majority around town, I'm getting around 14.7 mpg. Took it on 200 mile run yesterday with a couple of good grades and squeaked out 19.5 mpg. I miss the 36-gallon tank my Raptor had. I don't know why GM can't put in a larger tank in their gas guzzling trucks. My Raptor had a 600 mile range.