17 MPG combined is not a number that will excite drivers looking for less gas, but for the 2022 GMC Sierra Cab Chassis 2WD with the 5.3L V8, it’s a necessary compromise. This isn’t a lifestyle vehicle; it’s a workhorse, bought by contractors, landscapers, and small business owners who need a reliable platform to build a dump truck, flatbed, or service body. Fuel economy is secondary to capability, durability, and the proven performance of the tried-and-true 5.3L V8. This truck is designed to haul, tow, and endure, and to many owners, the fuel bill is simply a cost of doing business.

City and highway performance

The EPA estimates 15 MPG in city driving and 18 MPG on the highway. These figures reflect the realities of stop-and-go traffic, frequent acceleration with a heavy vehicle, and the aerodynamic compromises inherent in a cab chassis design. A fully loaded Sierra Cab Chassis won’t see anything close to 18 MPG on the highway, especially if it’s fitted with a bulky service body. However, these numbers provide a baseline, allowing owners to budget for fuel costs based on their typical usage patterns. The 10-speed automatic transmission does its best to optimize fuel efficiency, even under heavy loads, but there’s no cheating physics, moving mass requires energy.

Annual fuel cost

The EPA estimates an annual fuel cost of $2,600 for the 2022 GMC Sierra Cab Chassis 2WD 5.3L 8-cyl. This figure is based on driving 15,000 miles per year, with 45% of those miles driven in the city and 55% on the highway, and using the EPA’s estimate of the average fuel price at the time of calculation. Individual fuel costs will vary depending on driving habits, local fuel prices, and the actual workload the truck is subjected to. Someone primarily using their Sierra for short trips in the city while heavily loaded might see a much higher annual fuel cost, while someone who drives mostly highway miles without a heavy load might see somewhat better.

Real-world expectations

Forget marketing brochures, the real-world fuel economy of the Sierra Cab Chassis is heavily dependent on its configuration and usage. A flatbed model used primarily for light hauling on the highway might achieve numbers closer to the EPA estimate. On the other hand, a heavily loaded dump truck operating in a construction zone will likely see significantly lower MPG. Weather also plays a factor.

Cold temperatures and snow can significantly reduce fuel economy due to increased rolling resistance, longer warm-up times, and the use of four-wheel drive (if equipped). Ultimately, owners need to track their own fuel consumption to gain a true understanding of what their specific truck can achieve in their operating environment.

How it compares

Compared to its rivals, the 2022 GMC Sierra Cab Chassis 2WD 5.3L V8 doesn’t stand out as particularly fuel-efficient, or inefficient. A comparable Ford F-350 DRW chassis cab with the 7.3L gas V8 is EPA-rated at 14 MPG combined. The RAM 3500 chassis cab with the 6.4L Hemi V8 is rated around 15 MPG combined. Diesel alternatives generally offer better fuel economy, a Ford F-350 with the 6.7L Power Stroke diesel enjoys nearly 19 MPG combined, but come with a higher purchase price, increased maintenance costs, and the complexities of diesel emissions systems. For buyers prioritizing upfront cost and long-term reliability, the 5.3L V8 in the Sierra Cab Chassis offers a balanced approach, even if it sacrifices some fuel economy.

Tips to maximize efficiency

Tire pressure is critical. Regularly check and maintain the correct tire pressure, as indicated on the door placard. Under-inflated tires create more rolling resistance, which significantly reduces fuel economy, especially when carrying heavy loads. This truck is designed to carry weight, so inflate those tires accordingly.

Avoid excessive idling. The 5.3L V8 consumes fuel even when stationary. If you anticipate being stopped for more than a minute, especially in a construction zone or at a delivery site, turn off the engine. While frequent starts can put extra strain on components, extended idling burns fuel needlessly.

Drive smoothly and anticipate traffic conditions. Avoid aggressive acceleration and abrupt braking. The 10-speed automatic transmission is designed to keep the engine in its optimal efficiency range, so let it do its job. Give yourself plenty of following distance to avoid sudden stops, and use cruise control on the highway when appropriate.

Reduce aerodynamic drag where possible. Aftermarket accessories can impact fuel economy. Consider the impact of ladder racks, toolboxes, and service bodies on the vehicle’s aerodynamics. Choose designs that minimize drag and ensure they are properly installed to avoid unnecessary wind resistance. Cleaning mud flaps and fenders can provide results.

Consider using a fuel additive designed to clean fuel injectors and improve combustion. Over time, carbon deposits can build up in the engine, reducing its efficiency. Using a quality fuel additive can help restore lost performance and improve fuel economy, but only if combined with all other tips mentioned. Explore all Gmc fuel economy data and SIERRA MPG across all years to see how this truck compares to others.