2020 GMC Sierra 4WD AT4 MPG and Fuel Economy

On this page, you will find a complete guide to the miles per gallon and fuel efficiency data for the 2020 GMC Sierra 4WD AT4.

The 2020 GMC Sierra 4WD AT4 has 5 model options: Automatic 8-spd 8-cyl, 5.3 L, Automatic 10-spd 8-cyl, 5.3 L, Automatic 10-spd 8-cyl, 6.2 L, Automatic 6-spd 8-cyl, 5.3 L and Automatic 10-spd 6-cyl, 3.0 L.

The 2020 GMC Sierra 4WD AT4 Automatic 8-spd 8-cyl, 5.3 L runs on regular gasoline and is in the Standard Pickup Trucks 4WD car class.

The 2020 GMC Sierra 4WD AT4 Automatic 10-spd 8-cyl, 5.3 L runs on regular gasoline and is in the Standard Pickup Trucks 4WD car class.

The 2020 GMC Sierra 4WD AT4 Automatic 10-spd 8-cyl, 6.2 L runs on premium gasoline and is in the Standard Pickup Trucks 4WD car class.

The 2020 GMC Sierra 4WD AT4 Automatic 6-spd 8-cyl, 5.3 L runs on regular gasoline and is in the Standard Pickup Trucks 4WD car class.

The 2020 GMC Sierra 4WD AT4 Automatic 10-spd 6-cyl, 3.0 L runs on diesel and is in the Standard Pickup Trucks 4WD car class.

🛣 How Many Miles per Gallon (MPG) Does a 2020 GMC Sierra 4WD AT4 Get?

Across all models, the combined average MPG for the 2020 GMC Sierra 4WD AT4 is 19 miles per gallon.

The table below breaks down the MPG for each model option:

Model OptionCombined MPGCity MPGHighway MPG
Automatic 8-spd 8-cyl, 5.3 L181621
Automatic 10-spd 8-cyl, 5.3 L181621
Automatic 10-spd 8-cyl, 6.2 L171519
Automatic 6-spd 8-cyl, 5.3 L161418
Automatic 10-spd 6-cyl, 3.0 L242226

💵 What is the Average Yearly Fuel Cost for a 2020 GMC Sierra 4WD AT4?

The average fuel costs for all models of the 2020 GMC Sierra 4WD AT4 is $3,690.

The average fuel costs have been estimated by government regulators based on 15,000 miles driven per year, using regular gasoline, and a split of 55% city driving and 45% highway driving.

Comparing a 2020 GMC Sierra 4WD AT4 to an average vehicle over 5 years, you will spend $6,950 more on fuel.

The table below shows the fuel costs and 5-year save/spend for each model option:

Model OptionFuel Cost5-Year Save/Spend
Automatic 8-spd 8-cyl, 5.3 L$3,500spend $6,000 more
Automatic 10-spd 8-cyl, 5.3 L$3,500spend $6,000 more
Automatic 10-spd 8-cyl, 6.2 L$4,350spend $10,250 more
Automatic 6-spd 8-cyl, 5.3 L$3,900spend $8,000 more
Automatic 10-spd 6-cyl, 3.0 L$3,200spend $4,500 more

🛢 How Many Barrels of Petroleum Does a 2020 GMC Sierra 4WD AT4 Consume?

Across all models, the average number barrels of petroleum that the 2020 GMC Sierra 4WD AT4 will consume in one year is 17 barrels.

The majority of the world's petroleum is sourced from countries like Saudi Arabia, Russia, Iraq, and the United States.

Model OptionBarrels
Automatic 8-spd 8-cyl, 5.3 L17
Automatic 10-spd 8-cyl, 5.3 L17
Automatic 10-spd 8-cyl, 6.2 L18
Automatic 6-spd 8-cyl, 5.3 L19
Automatic 10-spd 6-cyl, 3.0 L15

💨 How Many Grams of CO2 Does a 2020 GMC Sierra 4WD AT4 Emit?

The 2020 GMC Sierra 4WD AT4 will emit an average of about 7,434,000 grams of CO2 per year.

🌳 To help you understand the impact of this, a normal tree will absorb around 21,000 grams of CO2 per year. This means that roughly 253 trees would be needed to offset emissions from the 2020 GMC Sierra 4WD AT4.

Overview

The tables below cover all of the miles per gallon, engine specifications, and emission details we have for the 5 2020 GMC Sierra 4WD AT4 model options.

Automatic 8-spd 8-cyl, 5.3 L

The table below contains all of the details we have for the 2020 GMC Sierra 4WD AT4 Automatic 8-spd 8-cyl, 5.3 L:

City MPG16
Highway MPG21
Combined MPG18
Save/Spend vs Average CarSpend $6,000
Fuel Cost$3,500
Fuel Type 1Regular
Barrels of Petroleum17
Grams of CO27,290,000
Trees Needed to Offset347
Drive4-Wheel Drive
Cylinders8
Displacement5.3
TransmissionAutomatic 8-spd
Vehicle ClassStandard Pickup Trucks 4WD
Start/Stop?Yes
Supercharged?No
Turbocharged?No

Automatic 10-spd 8-cyl, 5.3 L

The table below contains all of the details we have for the 2020 GMC Sierra 4WD AT4 Automatic 10-spd 8-cyl, 5.3 L:

City MPG16
Highway MPG21
Combined MPG18
Save/Spend vs Average CarSpend $6,000
Fuel Cost$3,500
Fuel Type 1Regular
Barrels of Petroleum17
Grams of CO27,410,000
Trees Needed to Offset353
Drive4-Wheel Drive
Cylinders8
Displacement5.3
TransmissionAutomatic 10-spd
Vehicle ClassStandard Pickup Trucks 4WD
Start/Stop?Yes
Supercharged?No
Turbocharged?No

Automatic 10-spd 8-cyl, 6.2 L

The table below contains all of the details we have for the 2020 GMC Sierra 4WD AT4 Automatic 10-spd 8-cyl, 6.2 L:

City MPG15
Highway MPG19
Combined MPG17
Save/Spend vs Average CarSpend $10,250
Fuel Cost$4,350
Fuel Type 1Premium
Barrels of Petroleum18
Grams of CO27,725,000
Trees Needed to Offset368
Drive4-Wheel Drive
Cylinders8
Displacement6.2
TransmissionAutomatic 10-spd
Vehicle ClassStandard Pickup Trucks 4WD
Start/Stop?Yes
Supercharged?No
Turbocharged?No

Automatic 6-spd 8-cyl, 5.3 L

The table below contains all of the details we have for the 2020 GMC Sierra 4WD AT4 Automatic 6-spd 8-cyl, 5.3 L:

City MPG14
Highway MPG18
Combined MPG16
Save/Spend vs Average CarSpend $8,000
Fuel Cost$3,900
Fuel Type 1Regular
Barrels of Petroleum19
Grams of CO28,340,000
Trees Needed to Offset397
Drive4-Wheel Drive
Cylinders8
Displacement5.3
TransmissionAutomatic 6-spd
Vehicle ClassStandard Pickup Trucks 4WD
Start/Stop?No
Supercharged?No
Turbocharged?No

Automatic 10-spd 6-cyl, 3.0 L

The table below contains all of the details we have for the 2020 GMC Sierra 4WD AT4 Automatic 10-spd 6-cyl, 3.0 L:

City MPG22
Highway MPG26
Combined MPG24
Save/Spend vs Average CarSpend $4,500
Fuel Cost$3,200
Fuel Type 1Diesel
ATV TypeDiesel
Barrels of Petroleum15
Grams of CO26,405,000
Trees Needed to Offset305
Drive4-Wheel Drive
Cylinders6
Displacement3
TransmissionAutomatic 10-spd
Vehicle ClassStandard Pickup Trucks 4WD
Start/Stop?Yes
Supercharged?No
Turbocharged?Yes

Link To or Reference This Page

If you use this page in your research, please reference MPG Buddy as the source.

  • "2020 GMC Sierra 4WD AT4 MPG and Fuel Economy." MPG Buddy. Accessed on January 3, 2026. https://mpgbuddy.com/cars/gmc/sierra-4wd-at4/2020.

  • "2020 GMC Sierra 4WD AT4 MPG and Fuel Economy." MPG Buddy, https://mpgbuddy.com/cars/gmc/sierra-4wd-at4/2020. Accessed January 3, 2026.

  • 2020 GMC Sierra 4WD AT4 MPG and Fuel Economy. MPG Buddy. Retrieved from https://mpgbuddy.com/cars/gmc/sierra-4wd-at4/2020.