The EPA estimates 17 MPG combined for the 2017 GMC Sierra K15 Cab Chassis 4WD with the 5.3L V8. No one buys this truck for great fuel mileage. They buy it because they need a capable, reliable platform to build a work truck, a tow rig, or a highly customized vehicle. Fuel economy is simply a known cost of doing business.

City and highway performance

The EPA breaks down that 17 MPG combined rating into 15 MPG in the city and 19 MPG on the highway. Those aren’t numbers that will win any awards, but they show a truck that prioritizes capability over outright efficiency. The 5.3L V8 provides ample power for hauling and towing, but it’s an older design that doesn’t incorporate the advanced fuel-saving technologies found in some newer engines. The 6-speed automatic transmission also plays a role. More modern trucks often feature 8 or 10-speed transmissions that allow the engine to operate more frequently in its most efficient range.

Annual Fuel Cost

The EPA estimates the annual fuel cost for the 2017 GMC Sierra K15 Cab Chassis 4WD 5.3L 8-cyl at $2,600. This figure is based on driving 15,000 miles per year, with 55% of those miles driven in the city and 45% on the highway. It also assumes gasoline priced at the national average. Your actual fuel costs will vary depending on your driving habits, the type of work you do, and local fuel prices, but $2,600 gives you a solid baseline for budgeting.

Real-world expectations

The EPA provides a standardized testing procedure, so you should manage your expectations for real-world fuel economy. Factors like load weight, towing, driving style, and terrain can significantly impact your MPG. Those using this truck for heavy-duty work or frequent towing are likely to see figures below the EPA estimates. Drivers who primarily use the truck for lighter tasks and highway cruising may be able to achieve numbers closer to, or even slightly above, the 19 MPG highway rating. Monitoring your fuel consumption and adjusting driving habits are key to optimizing fuel economy in the real world.

How it compares

Compared to other trucks in its class and vintage, the 2017 GMC Sierra K15 Cab Chassis lands roughly in the middle of the pack for fuel economy. A similar Ford F-150 with the 5.0L V8 and four-wheel drive achieves an EPA-estimated 18 MPG combined. The Ram 1500 with the 5.7L Hemi and four-wheel drive is rated at 17 MPG combined, matching the Sierra. Newer trucks with advanced engine technologies and more transmissions often deliver better fuel economy. For example, a 2023 Ford F-150 with the 2.7L EcoBoost V6 and four-wheel drive achieves 21 MPG combined. This comparison matters to some buyers who are also weighing newer, more fuel-efficient trucks. Potential owners should browse all Gmc fuel economy data to understand the brand’s efficiency profile.

Tips to maximize efficiency

Regular maintenance is critical for optimizing fuel economy. Ensure your engine is properly tuned, your tires are correctly inflated, and your air filter is clean. A well-maintained engine runs more efficiently, and properly inflated tires reduce rolling resistance, which can translate to small but meaningful gains in MPG. Keep up with all scheduled maintenance to avoid larger issues that affect fuel economy.

Avoid unnecessary idling. Idling consumes fuel without covering any distance. If you anticipate being stopped for more than a minute, it’s generally more fuel-efficient to turn off the engine and restart it when you’re ready to go. This is especially true for older engines like the 5.3L V8 in the 2017 Sierra, as they are not optimized like newer engines with stop/start technology.

Minimize aerodynamic drag. Since this is typically a chassis cab model, owners may upfit this with different kinds of truck bodies. Think carefully about the shape of the body to minimize drag at highway speeds. Avoid driving at excessive speeds unless doing so is necessary to keep pace with commercial traffic.

Use cruise control on the highway. Maintaining a consistent speed helps to improve fuel economy, as it eliminates unnecessary acceleration and deceleration. Setting the cruise control on relatively flat stretches of road allows the engine to operate at a more consistent and efficient level, especially given how SIERRA MPG across all years can vary.

Drive smoothly and avoid aggressive acceleration and braking. Gentle acceleration and deceleration conserve fuel and reduce wear and tear on your vehicle. Anticipate traffic conditions and maintain a safe following distance to avoid sudden stops. Think carefully about route planning to minimize stoplights and mileage.