MPG at 600 miles

2021 HD · September 10, 2023

I am getting 12.9 MPG all around town in my 24 6.6 gas job. The truck is saying 12.7. This is with 600 miles on it. If I can get 14 MPG when broken in I will be happy.

Dunn · September 11, 2023

I get around 12.3 in 23 model, worse in heavy stop and go

Heard in 24s the biggest benefit is towing....otherwise pretty much same

My 2022 LT was bit better than H.C. I have now....not much but lil bit

Tater86 · September 11, 2023

I've been sitting around 14.8 with a mix of city and highway driving since mile 1 and I have 2000 on it now. This tank I'm sitting at 15.1.

mrjulian416 · September 11, 2023

Over a total of 35k miles, I have never reset "trip 2" on the odometer. Combined calculated is 15.1. That includes around town, highway trips, occasional moderate and heavy towing.

I also glance at the "last 25" calculated mileage from time to time. Around town that will be 11-12.5. On highway that will be 18-20.5. Towing... just don't look.

Of course, your mileage may vary, literally.

sigmonster · September 12, 2023

I have a 2024 High country gas with 3000 miles.

Stop and go driving(city) kills the gas mileage to a 12-13 mpg average.

Driving hard (75-85 mph) on the interstate gives about 14 mpg. Drafting of slowing down to 70-75 gives 15 mpg.

Driving 60-65 gives 16 mpg and drafting at 60-65 gives 17 mpg.

Towing 2500 lb at 60-65 gives 11 mpg.

Towing 14,000 lb at 60 gives 7-8 mpg.

My mileage has improved after the first 1500-2000 miles and may get a little better.

Zero oil usage and the oil is still very light brown.

The truck is not quick, but plenty of acceleration when needing to merge (unloaded).

It pulls a 14,000 lb boat remarkably well--I did add the Timbren axle stops so I have very little squat or bouncing.

Overall, I love the truck

KARNUT · September 12, 2023

It would be a great comparison to see what a 1/2 tons gas mileage is with a max trailing package. Especially for people who tow under 12K and do it less than 1/2 the time. My 14 GMC had a trailer package and got 22 mpg at 72 mph empty.

sigmonster · September 13, 2023

I had a 2017 Sierra with the 6.2 and max tow. Very quick truck and great towing 5-6,000 lb. It got 19 mpg driving hard (75-85) and over 20 mpg driving 70-75, but that was using either premium or 89 ethanol free. It got 10-12 mpg towing a 5,000 lb boat 75 mph. It was a great truck, but not up to towing my new boat. I will say my new 2500 rides more smoothly and quietly; it is just harder to park-LOL.

UWSkier · September 13, 2023

On 9/12/2023 at 5:48 AM, sigmonster said:

I have a 2024 High country gas with 3000 miles.

Stop and go driving(city) kills the gas mileage to a 12-13 mpg average.

Driving hard (75-85 mph) on the interstate gives about 14 mpg. Drafting of slowing down to 70-75 gives 15 mpg.

Driving 60-65 gives 16 mpg and drafting at 60-65 gives 17 mpg.

Towing 2500 lb at 60-65 gives 11 mpg.

Towing 14,000 lb at 60 gives 7-8 mpg.

My mileage has improved after the first 1500-2000 miles and may get a little better.

Zero oil usage and the oil is still very light brown.

The truck is not quick, but plenty of acceleration when needing to merge (unloaded).

It pulls a 14,000 lb boat remarkably well--I did add the Timbren axle stops so I have very little squat or bouncing.

Overall, I love the truck

This is about what I am seeing in my 2024 LTZ with 7000 miles. I got 19 MPG driving at 60 MPH with a tailwind once so far, but most everything else jives with what you've posted.

Comparing to my 2016 Denali half ton 4wd with 5.3L, I get about 2 MPG worse in everyday driving, but about 1 MPG better towing in pretty much all conditions.

2021 HD · September 15, 2023

I forgot to say that 12.9 mpg is all around town but 1/2 the time having around 800 lbs in the back. the most in the back i have had so far is 2200 lbs.

Jettech1 · September 15, 2023

4 hours ago, 2021 HD said:

I forgot to say that 12.9 mpg is all around town but 1/2 the time having around 800 lbs in the back. the most in the back i have had so far is 2200 lbs.

I would say you are right in the normal range. These trucks are heavy as hell, so getting say 13 to 14 around town unloaded sounds quite normal.

BCGM · June 1

My brain matter is shrinking in my latter years . When you quote MPG that is for a US gallon which is smaller than a Canadian gallon .

#1 Am I right in thinking that the MPG would not be the same or am I confused ?

#2 What would your fuel consumption be if you posted it as Liters per 100 Kilometers as Fuel economy is expressed here in Canada L/100Klm ?

Thank you

Capt Bob · June 2

22 hours ago, BCGM said:

My brain matter is shrinking in my latter years .

#2 What would your fuel consumption be if you posted it as Liters per 100 Kilometers as Fuel economy is expressed here in Canada L/100Klm ?

Thank you

Using a conversion calculator 12 MPG (about what I get around town) converts to 19.6 liters per 100klm

BCGM · June 2

1 hour ago, Capt Bob said:

Using a conversion calculator 12 MPG (about what I get around town) converts to 19.6 liters per 100klm

Thanks Capt Bob . I think I'm getting better than that but will check next time I'm in the truck as I'm not driving it much as it is a thirsty beast ,LOL ! I will post a update

lineman1234 · June 3

On 9/11/2023 at 6:46 AM, mrjulian416 said:

Over a total of 35k miles, I have never reset "trip 2" on the odometer. Combined calculated is 15.1. That includes around town, highway trips, occasional moderate and heavy towing.

I also glance at the "last 25" calculated mileage from time to time. Around town that will be 11-12.5. On highway that will be 18-20.5. Towing... just don't look.

Of course, your mileage may vary, literally.

I dont see if it is a gasser or diesel? I know its an older post, but the highway mileage seems to good to be true.

I drive very nice and its flat hear. Almost 10,000 miles on my 6.6 gasser and i havent gotten 17mpg on a tank yet, mostly rural 55-60mpg roads. I also havent gotten a tank of non ethanol hear either. Ethanol meaning 10%, not E85.

Not much of town driving around hear, so i dont know on that.

But, tank to tank, fill ups with diesel being more than gas, its still cheaper to feed my gasser than my last diesel.

Edited June 3 by lineman1234

Dunn · June 3

if I stayed on highway I would get 17 mpg in so cal, 21 is my best from Burbank to Long beach no traffic before i hit city streets.....driving 60-65, but always have to mix it with city

on trip home from dealership I was at 17 plus on new motor from Phoenix to LA, and I was hauling ass for good portion late at night

problem is my area is littered with stop signs every block so its 8-9mpg in town

the computer isn't far off real world calculations.....few tenths maybe