2016 Sierra All Terrain GAS MILEAGE !

Snowmobile Mike · April 11, 2019

Had truck about a little over two months ! It has THE 8 speed transmission and the ( I think ) 3.2 something rear end, I gave vin number to dealer yesterday he said correct rear end for best gas mileage not 3.7 or 3.8 ???

Gas mileage around town last 100 miles around 11 mpg. At times I've seen 16 maybe 17 on HGW. It seems best around town is probably 12.

I've been looking for a truck like this for awhile with the assumption that the sticker of 17 -23 MPG is close ! WHAT IS THE PROBLEM ? Gas mileage is NOT what I expected ??? Also I notice a small when its fired up, just doesn't smell NORMAL !!!

damnthetorpedoes · April 11, 2019

That honestly doesn't sounds too far off. Has anything been done to it - tires, lift/level, etc.?

What does it smell like?

KARNUT · April 11, 2019

Something is definitely wrong with the gas mileage for a midsize V6 SUV. I’ve seen better in a full-size SUV. My V-6 6 speed Santa Fe got 27 mpg at 75 mph for thousands of miles. 30 mpg at 60. 22 in town.

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4weight · April 11, 2019

3 hours ago, Snowmobile Mike said:

Had truck about a little over two months ! It has THE 8 speed transmission and the ( I think ) 3.2 something rear end, I gave vin number to dealer yesterday he said correct rear end for best gas mileage not 3.7 or 3.8 ???

Gas mileage around town last 100 miles around 11 mpg. At times I've seen 16 maybe 17 on HGW. It seems best around town is probably 12.

I've been looking for a truck like this for awhile with the assumption that the sticker of 17 -23 MPG is close ! WHAT IS THE PROBLEM ? Gas mileage is NOT what I expected ??? Also I notice a small when its fired up, just doesn't smell NORMAL !!!

My 2017 has a level on it and I run 33x12.5x20 Toyo AT2's. With no wind Tuesday, I got 20.9 highway on a 3 hour trip. Into a 25-30 headwind yesterday, I ran about 15. I run 14-15 around town and have never gotten 12 unless I was towing.

aseibel · April 11, 2019

The most common gears are 3.08 or 3.42.

3.08 is slightly better for economy, while 3.42 is for more torque/towing.

I think there is a 3.23 also, but I haven't seen too many people with that.

I have 3.42. I can get 11 mpg for a tank when I have my plow on in winter and only drive in town. That would be pretty bad for an unloaded truck. But if you are in heavy traffic or with a lot of stop signs and lights, I'm not shocked you would be under 15 mpg. Too many unknown variables for anyone to predict what you should be getting.

Try driving a longer round trip with cruise control at 70 mph or less to see what you can get ideally on the highway. Higher speeds also kill your fuel mileage.

Snowcamo · April 11, 2019

[emoji35][emoji35][emoji35] Also I notice a small (???)when its fired up, just doesn't smell NORMAL !!!

Gas?
Can you elaborate please?

MaverickZ71 · April 11, 2019

Sounds normal to me. My 5.3L 6-speed Silverado's window sticker said 14 city 19 hwy. Never ever got that, even back when AFM was still activated, with a big tailwind. In warm weather, I get 12 city and 17 hwy. In cold weather with remote starts, I get 10 city. And that's using mid-grade or premium gas. Using regular, it pings a little and gets a little bit less mpg. They used to say to use the EPA's city fuel economy rating number for your real-world combined city/hwy mileage, and you'd be about right. I believe that. Also remember that the mpg testing is done on 100% gas, and 10% or 15% ethanol at the pumps reduces our real-world mpg.

Edited April 11, 2019 by MaverickZ71

garagerog · April 11, 2019

1 hour ago, KARNUT said:

Something is definitely wrong with the gas mileage for a midsize V6 SUV. I’ve seen better in a full-size SUV. My V-6 6 speed Santa Fe got 27 mpg at 75 mph for thousands of miles. 30 mpg at 60. 22 in town.

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He's talking about a Sierra AT, not the GMC Terrain CUV.