16 MPG combined isn’t going to win any green awards, but it also isn’t a shock for the 2023 GMC Sierra Cab Chassis 4WD equipped with the 5.3L V8. This isn’t a family grocery-getter or a commuter car. It’s a workhorse, designed for businesses and individuals who need a reliable platform for upfitting into a service truck, ambulance, utility vehicle, or countless other specialized applications. Fuel economy, while always a consideration, often takes a backseat to capability, payload, and the ability to get the job done.

City and highway performance

The EPA estimates the Sierra Cab Chassis at 15 MPG in the city and 17 MPG on the highway. This is a relatively small difference between urban and open-road driving, mainly because this vehicle is rarely driven unloaded, and even less frequently driven gently. The 5.3L V8, while a proven and reliable engine, is working hard to move a heavy chassis designed to carry significant loads. Expect these figures to drop even further when the truck is fully loaded, towing, or operating with specialized equipment in use. A lighter foot might improve efficiency slightly, but the engine’s inherent characteristics and the vehicle’s weight mean substantial gains are unlikely.

Annual fuel cost

The EPA calculates the annual fuel cost for the 2023 GMC Sierra Cab Chassis 4WD 5.3L at exactly $2,750. This figure is based on driving 15,000 miles per year, using the EPA’s combined MPG estimate, and assuming a national average fuel price. This cost is a significant business expense for owners, and it is often factored into operating budgets and pricing structures for their services. Remember that fluctuations in fuel prices and individual driving habits will influence the final annual cost. If you drive significantly more than 15,000 miles annually, or if fuel prices are higher in your region, you can expect to pay more.

Real-world expectations

Don’t expect to consistently match the EPA estimates in the real world, especially if you’re using the Sierra Cab Chassis as intended. Stop-and-go traffic in bustling work zones, prolonged idling while on the job site, and the increased rolling resistance of heavy-duty tires will drag down fuel economy. Users often report figures closer to 13-15 MPG in combined driving, particularly if they are frequently hauling heavy loads, towing trailers, or operating PTO-driven equipment. Factors like terrain, weather, and the type of upfit can also significantly affect fuel consumption. A fully-equipped service body with ladders and tools will undoubtedly have a greater impact than a relatively bare chassis. The ten-speed automatic transmission helps optimize engine efficiency, but it cannot overcome the inherent demands of heavy work.

How it compares

Compared to other heavy-duty truck chassis, the 2023 GMC Sierra Cab Chassis 4WD 5.3L’s fuel economy is within the expected range. A Ford F-350 Super Duty chassis with the 6.8L V8 reports similar fuel economy numbers. For a gas engine setup, the figures align, especially between models sharing similar gross vehicle weight ratings (GVWR). A diesel-powered chassis tends to offer better fuel economy for heavy work. However, diesel options also bring higher initial costs, maintenance expenses, and potential emissions concerns. Consider a RAM 5500 chassis cab with the Cummins diesel, typically delivering around 17-19 MPG combined, although this comes with a significantly higher upfront investment. The main reason for choosing a Sierra Cab Chassis isn’t fuel efficiency, but rather its blend of capability, reliability, and overall cost-effectiveness. Buyers prioritize its proven track record, extensive dealer and service network, and its suitability for specific upfitting needs.

Tips to maximize efficiency

Ensure proper tire inflation. The recommended tire pressure for your specific tire size and load rating is critical for minimizing rolling resistance. Check tire pressure regularly, especially before long trips or heavy hauls. Low tire pressure increases friction and can significantly reduce fuel economy.

Avoid excessive idling. Idling consumes fuel without covering any distance and quickly lowers your mileage. If you’re going to be stationary for more than a few minutes, shut off the engine. This simple habit can save a surprising amount of fuel over time.

Maintain a steady speed. Rapid acceleration and hard braking consume more fuel than gentle, gradual transitions. Anticipate traffic flow and maintain a consistent speed whenever possible. This is especially important on the highway.

Keep up with scheduled maintenance. Regular oil changes, air filter replacements, and tune-ups ensure your engine is running efficiently. A properly maintained engine will deliver optimal performance and fuel economy. Refer to your owner’s manual for the recommended service intervals.

Consider removing unnecessary weight. While the Sierra Cab Chassis is designed for heavy loads, carrying around excessive, unused equipment will negatively impact fuel economy. Periodically assess your cargo and remove any items that are not essential for the task at hand.

Browse all Gmc fuel economy data. You can also find SIERRA MPG across all years.