15 MPG combined is what you get with the 2019 GMC Sierra K10 Cab Chassis 4WD with the 4.3L V6. This isn’t a vehicle bought for saving fuel, it’s purchased by businesses and individuals who need a strong, reliable workhorse, and the fuel economy is simply a cost of doing business. Contractors, landscapers, and small business owners who prioritize capability and configurability over Prius-like efficiency need a truck ready for upfitting with a service body, dump bed, or any other specialized configuration, and the K10 Cab Chassis delivers exactly that, even if it’s not winning any fuel-sipping contests.

City and highway performance

The EPA rates the 2019 Sierra K10 Cab Chassis at 14 MPG in the city and 17 MPG on the highway. These figures reflect the reality of a heavy-duty truck navigating stop-and-go traffic and maintaining highway speeds with a focus on durability rather than aerodynamics. The 4.3L V6, while a competent engine, works hard pushing the Sierra’s considerable weight, especially when loaded. Highway MPG can drop further when towing or hauling heavy loads, which is the truck’s intended purpose. Expect the transmission to frequently downshift on inclines to maintain speed, further impacting fuel consumption. To see SIERRA MPG across all years explore other body and powertrain options.

Annual fuel cost

The EPA estimates that the annual fuel cost for the 2019 GMC Sierra K10 Cab Chassis 4WD with the 4.3L V6 is $2,900. This figure is based on driving 15,000 miles per year and using national average fuel prices. Potential buyers should factor this significant expense into their total cost of ownership.

Fuel prices fluctuate, and individual driving habits vary, so the $2,900 provides a clear indication of the fuel costs associated with operating this particular vehicle under average conditions.

Real-world expectations

Don’t expect to consistently match the EPA’s ratings. Real-world fuel economy will vary based on several factors. Aggressive driving, frequent towing, and prolonged idling will all negatively impact your MPG. Cold weather can also decrease fuel economy as the engine works harder to reach optimal operating temperatures. Properly maintaining the vehicle, including regular oil changes and tire inflation, can help optimize fuel efficiency, but ultimately, the nature of this vehicle means it will never be a fuel saver.

How it compares

Compared to other similarly purposed vehicles, the Sierra K10’s fuel economy is generally in line with expectations for its class. A comparable Ford F-350 XL Regular Cab 4×4 with the 6.2L V8 is rated at 15 MPG combined. Ram 3500 Tradesman Regular Cab 4×4 with the 6.4L V8 manages a similar 14 MPG combined.

These trucks are not purchased for MPG, so buyers of these chassis cabs don’t tend to view the fuel economy as a major differentiator. They are concerned with the reliability of the powertrain and the truck’s ability to handle the specific upfitting and workload they require. For those interested in comparing all Gmc fuel economy data, various resources are available.

Tips to Maximize Efficiency

Avoid excessive idling. This is particularly crucial for a vehicle like the Sierra K10, which consumes a significant amount of fuel even when stationary. If you anticipate being stopped for more than a minute, turn off the engine.

Monitor your tire pressure regularly. Underinflated tires increase rolling resistance, forcing the engine to work harder and reducing fuel efficiency. Maintain the recommended tire pressure as specified in the owner’s manual, especially when carrying heavy loads.

Drive smoothly and avoid aggressive acceleration and braking. The 4.3L V6 responds best to a gentle touch. Anticipate traffic flow and maintain a steady speed whenever possible to minimize fuel consumption.

Consider the weight of your upfit. While the Sierra K10 is designed to handle significant weight, every pound added reduces fuel economy. Choose lighter materials for your upfit when possible and avoid carrying unnecessary equipment.

When possible, plan routes that minimize stop-and-go driving. Highway MPG will always be better than city MPG for this vehicle, so optimizing routes for less in-town driving should improve your fuel expenditure. Even optimizing by a few miles per day can save money over the long haul.