17 MPG combined isn’t going to win any awards, but for the 2016 GMC Sierra C15 Cab Chassis 2WD with the 5.3L V8, it’s simply part of the cost of doing business. This isn’t a grocery-getter or a commuter car. This is a workhorse, built to be upfitted with everything from dump beds to service bodies, and then spend its days hauling materials and equipment to job sites.

City and highway performance

The EPA estimates 15 MPG in the city and 20 MPG on the highway for this particular Sierra configuration. This split reflects the engine’s workload. Around town, stop-and-go driving and idling obviously hurt fuel economy. Highway efficiency is slightly better, but even then, the Sierra’s size and weight, coupled with the inherent thirst of a naturally aspirated 5.3L V8, prevent it from achieving truly impressive mileage figures. This engine, while reliable and offering ample power, prioritizes capability over fuel sipping. The 6-speed automatic transmission does what it can, but it’s geared for pulling power and durability, not for maximizing fractions of a mile per gallon.

Annual fuel cost

The EPA estimates an annual fuel cost of $2,600 for the 2016 GMC Sierra C15 Cab Chassis 2WD 5.3L 8-cyl. This figure is based on driving 15,000 miles per year, with a mix of city and highway driving, and using national average fuel prices. Buyers considering this vehicle understand that this is just an estimate. A heavily loaded Sierra constantly working on a construction site will inevitably exceed that figure. This is less of a surprise and more of an expected cost for those who rely on this type of truck. You can view all Gmc fuel economy data to see how other GMC trucks fare.

Real-world expectations

Don’t expect to consistently match the EPA numbers. Real-world fuel economy varies greatly depending on load, driving style, and terrain. A lightly loaded Sierra on a flat highway might approach or even slightly exceed 20 MPG, but add a few thousand pounds of payload, or frequent trips through hilly terrain, and you’ll see those numbers drop considerably.

Owners often find averages closer to 12-15 MPG in mixed driving, especially if the truck is regularly used for heavy-duty tasks. The priority for these buyers isn’t saving money at the pump; it’s getting the job done reliably, day in and day out. They are willing to accept the fuel costs associated with the truck’s capabilities.

How it compares

Compared to its rivals, the 2016 Sierra C15 Cab Chassis’s fuel economy is largely within the expected range for this class of vehicle. The Ford F-150 XL Regular Cab with the 5.0L V8, for example, achieves a similar 17 MPG combined. A Ram 1500 Tradesman with the 5.7L Hemi might even be closer to 15 MPG combined. The fuel economy of the Sierra, therefore, isn’t a major differentiating factor when choosing between these trucks. What matters more is the specific needs of the buyer, such as payload capacity, upfitting options, and overall reliability. Looking at SIERRA MPG across all years can help to give a broader perspective.

Tips to maximize efficiency

While exceptional fuel economy isn’t the Sierra’s forte, there are still steps you can take to improve mileage. Avoid aggressive acceleration and hard braking. The 5.3L V8 responds well to a smooth, steady throttle, and excessive pedal stomping only wastes fuel. Anticipate traffic flow and maintain a consistent speed whenever possible.

Keep your tires properly inflated. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tire pressure regularly and inflate them to the manufacturer’s recommended levels. This is especially critical when hauling heavy loads.

Minimize idling. Extended periods of idling consume fuel without covering any distance. If you’re going to be stopped for more than a minute or two, turn off the engine. This simple habit can save a surprising amount of fuel over time, especially in a truck like this that spends considerable time on job sites.

Service your vehicle regularly. A well-maintained engine runs more efficiently. Follow the manufacturer’s recommended maintenance schedule, including oil changes, air filter replacements, and spark plug maintenance. Proper maintenance ensures that the engine is operating at its peak performance.

Consider the weight you carry. Remove any unnecessary tools or equipment from the truck bed. Extra weight reduces fuel economy, so only carry what you need for the job at hand. The less strain you put on the engine, the more efficient it will be.