17 MPG combined. That’s the number you’ll see when looking at the 2015 GMC Sierra C15 2WD with the 6.2L V8. It’s not the most efficient, but if you’re seriously considering this truck, fuel economy probably isn’t your main concern. This Sierra configuration prioritizes raw power and capability, made for those who need it and appreciate the roar of a big V8. It’s a choice often driven by wants, not needs, and a compromise accepted for the performance.

City and highway performance

The official EPA estimates put the city MPG at 15, while the highway figure rises to 21. This difference shows the engine’s characteristics. In stop-and-go traffic, the 6.2L V8 works hard, moving a heavy vehicle. The cylinder deactivation tries to help, but its effectiveness is limited in the city. However, on the open road, where you can maintain a steady speed and the 8-speed automatic transmission shifts into higher gears, the fuel economy improves. That 21 MPG isn’t going to win any fuel-sipping contests, but it’s good for a truck with this much power.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2015 GMC Sierra C15 2WD 6.2L V8 at $2,600. This is based on driving 15,000 miles per year, with a mix of city and highway driving, using the national average fuel price at the time. This means that depending on your location and driving style, your actual fuel costs could be higher or lower. The $2,600 provides a baseline for understanding the cost of owning this powerful pickup.

Real-world expectations

While the EPA numbers offer a standardized benchmark, real-world fuel economy can change based on driving habits, terrain, and weather. If you regularly tow heavy loads or spend most of your time in congested urban areas, expect numbers closer to the city estimate, or even lower. However, if you mainly use the truck for long highway trips and drive conservatively, you might approach or slightly exceed the EPA highway estimate. Quick acceleration and frequent use of the 6.2L’s horsepower will affect your MPG.

How it compares

The 2015 GMC Sierra C15 2WD 6.2L compares to other full-size trucks of its time. A similarly equipped Ford F-150 with the 5.0L V8 gets around 18 MPG combined. The Ram 1500 with its 5.7L Hemi is also close, at about 17 MPG combined. The main difference is the Sierra’s larger 6.2L engine, which focuses on power. For buyers interested in better fuel economy, the smaller V6 engine options are worth exploring, as well as all Gmc fuel economy data available for all models. You can view SIERRA MPG across all years as well to compare.

Tips to maximize efficiency

Avoid using the 6.2L’s full power. Gentle acceleration and a steady speed will make a difference. This engine is responsive, so light throttle inputs deliver power, reducing the need to push it hard.

Make sure your tires are properly inflated. Tire pressure impacts rolling resistance, and underinflated tires affect fuel economy. Check your tire pressure regularly and inflate them to the manufacturer’s specifications, listed on the sticker inside the driver’s side door.

Minimize idling. If you’re stopped for more than a minute, turn off the engine. Modern vehicles restart quickly, and idling consumes fuel. This is important in city driving.

Reduce weight. Carrying extra cargo in the truck bed or cabin reduces fuel economy. Remove items you don’t need regularly. Each pound increases fuel use.

Plan your trips. Combine errands and avoid peak traffic. Fewer stops and a consistent speed will improve fuel economy. Mapping the best route can save time and fuel.