17 MPG combined. That’s the reality for anyone choosing the 2021 GMC Sierra 1500 4WD with the big 6.2-liter V8. Let’s be clear: nobody buys this truck for its exceptional fuel efficiency. They buy it for its effortless power, its distinctive presence, and its ability to tow and haul with authority. For these buyers, fuel economy is a secondary consideration, a necessary evil accepted for the capabilities this specific configuration unlocks.

City and highway performance

The EPA estimates the 2021 GMC Sierra 4WD 6.2L V8 at 16 MPG in the city and 20 MPG on the highway. These numbers reflect the engine’s displacement and the truck’s considerable weight. Stop-and-go traffic will predictably drag down fuel economy as the engine works harder to accelerate the heavy vehicle. The 10-speed automatic transmission helps to optimize engine performance at various speeds, contributing to the 20 MPG highway figure, but physics ultimately dictate the limits of what can be achieved. Considering the Sierra’s imposing size and thirsty engine, the highway number is generally considered respectable.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2021 GMC Sierra 4WD 6.2L at $3,400. This figure is based on driving 15,000 miles per year and using national average fuel prices. Note that fuel prices fluctuate, and individual driving habits will significantly impact the actual amount spent. Someone who primarily drives short distances in the city will likely exceed this estimate, while someone who does mostly highway driving may see a slightly lower annual cost.

Real-world expectations

Expect to see figures close to the EPA estimates, but it’s important to understand what factors will influence your specific fuel economy. Aggressive driving, frequent towing, and the addition of aftermarket accessories like larger tires or roof racks will all decrease MPG. Conversely, gentle acceleration, consistent highway speeds, and meticulous maintenance can help you get closer to the EPA’s numbers. The type of gasoline used, though ostensibly “regular” in the EPA testing, can influence mileage slightly.

How it compares

Against competitors, the Sierra’s fuel economy is typical. A similar configuration Ford F-150 with the 5.0-liter V8 and four-wheel drive achieves an EPA-estimated 19 MPG combined. The Ram 1500 with the 5.7-liter Hemi and eTorque mild-hybrid system delivers around 17 MPG combined, virtually identical to the Sierra. It’s critical to compare similar engine sizes and drivetrain configurations. Choosing a smaller engine or two-wheel drive will, of course, improve fuel economy, but it will also sacrifice some of the capability that draws buyers to the 6.2-liter Sierra. Those willing to forego the V8 rumble can explore the turbocharged four-cylinder or diesel options; you’ll find SIERRA MPG across all years offers a range of choices.

Tips to maximize efficiency

Consider your driving style. Avoid aggressive acceleration and hard braking, as these habits significantly decrease fuel economy. The Sierra is a heavy truck, and stepping on the gas pedal to get up to speed quickly requires a lot of fuel. Instead, accelerate smoothly and gradually.

Keep your tires properly inflated. Underinflated tires increase rolling resistance, forcing the engine to work harder and using more fuel. Check your tire pressure regularly and inflate them to the recommended level, typically found on a sticker inside the driver’s side door.

Avoid unnecessary idling. If you’re stopped for more than a minute or two, it’s generally more fuel-efficient to turn off the engine. Modern engines are designed to restart quickly and easily, so you won’t cause any harm by switching it off.

Pay attention to the truck’s load. Carrying heavy cargo or towing a trailer will dramatically reduce fuel economy. Only carry what you need to, and when towing, make sure to distribute the weight evenly and use the correct hitch.

Regular maintenance is key. Ensure that your engine is properly tuned, and that all fluids are at the correct levels. Replace air filters on schedule and use the recommended oil viscosity. A well-maintained engine will run more efficiently and deliver better fuel economy. See all Gmc fuel economy data.