21 MPG combined in the 2022 GMC Sierra 1500 with mud-terrain tires, four-wheel drive, and the 3.0L Duramax diesel isn’t going to win any hypermiling contests, and GMC knows it. This truck isn’t engineered for maximizing every last drop of fuel, it’s built for capability above all else. It’s aimed squarely at buyers who prioritize off-road ability and strong durability over squeezing every last mile from a gallon of diesel.

City and highway performance

The EPA estimates 20 MPG in the city and 23 MPG on the highway for this particular configuration of the Sierra 1500. The slightly lower city MPG reflects the inherent inefficiency of stop-and-go driving in a heavy, four-wheel-drive truck equipped with aggressive mud-terrain tires. The highway figure demonstrates the potential for decent fuel economy when the engine settles into a cruising rhythm, and the aerodynamics are allowed to work in your favor. That said, don’t expect to consistently see 23 MPG if you’re running at 80 MPH with those mud tires singing.

Annual fuel cost

The EPA estimates that owners of this particular 2022 GMC Sierra configuration will spend $2,650 on fuel annually. This figure is based on driving 15,000 miles per year and using national average fuel prices. It’s a useful benchmark for comparing the running costs of different vehicles, but remember that your actual fuel expenses will depend on your driving habits, the specific roads you travel, and prevailing diesel prices in your area. Someone who tows heavy loads regularly or lives in an area with high fuel costs will undoubtedly exceed this estimate.

Real-world expectations

While the EPA numbers provide a standardized comparison, anecdotal evidence suggests that real-world MPG can vary considerably. Drivers who spend most of their time off-road or in heavily congested city conditions may find themselves closer to the high teens. Conversely, those who primarily use the truck for highway cruising, particularly without a heavy payload or trailer, may see figures approaching or even slightly exceeding the EPA highway estimate. Driving style also plays a significant role, aggressive acceleration and hard braking will always take a toll on fuel economy.

How it compares

Compared to other full-size trucks, the 2022 Sierra 1500 4WD with the 3.0L Duramax and mud-terrain tires holds its own. A similarly equipped Ford F-150 with the 3.5L EcoBoost V6 and FX4 package achieves around 19 MPG combined. The Ram 1500 with the 3.0L EcoDiesel, if you can find one, nets similar numbers to the Sierra. A gasoline-powered V8 version of the Sierra, even with cylinder deactivation, will likely return 16-18 MPG combined. For those looking for alternatives within the GMC portfolio, all Gmc fuel economy data shows comparable efficiencies depending on engine and trim level. However, if fuel economy is a *primary* concern, buyers should consider the two-wheel-drive version of the Sierra with the same diesel engine, which edges out the four-wheel-drive configuration. If you’re curious about SIERRA MPG across all years and configurations, there’s a wealth of data available online. It’s important, though, to remember that these trucks are built to haul, tow, and tackle tough terrain, which inherently compromises fuel efficiency compared to lighter-duty vehicles.

Tips to maximize efficiency

Ensure your tires are properly inflated. Mud-terrain tires, in particular, can experience increased rolling resistance when underinflated, negatively impacting fuel economy. Check your tire pressure regularly and inflate them to the recommended pressure listed on the driver’s side door jamb, taking into account any adjustments recommended by the tire manufacturer.

Avoid unnecessary idling. The Duramax diesel is a relatively efficient engine, but idling for extended periods consumes fuel without covering any distance. If you anticipate being stopped for more than a minute or two, it’s best to turn off the engine.

Drive smoothly and avoid aggressive acceleration. The 10-speed automatic transmission is designed to keep the engine in its optimal RPM range, but rapid acceleration forces the transmission to downshift, increasing fuel consumption. A more gradual and deliberate driving style will help maximize fuel efficiency.

Minimize aerodynamic drag. Removing any unnecessary roof racks, cargo carriers, or running boards can reduce aerodynamic drag and improve fuel economy, especially at higher speeds. Keeping the bed covered with a tonneau cover can also offer a slight advantage, although the benefits may be minimal.

Schedule regular maintenance. Keeping your engine properly tuned, ensuring clean air and fuel filters, and using the recommended engine oil can all contribute to optimal fuel efficiency. A well-maintained engine simply runs more efficiently than one that’s neglected.