17 MPG combined is what you can expect if you’re the kind of truck buyer who values raw power, confident towing, and a muscular exhaust note more than saving money on fuel. The 2019 GMC Sierra K10 4WD with the 6.2L V8 is not a fuel-efficient choice. It’s built for weekend warriors hauling boats, contractors lugging tools, and anyone who needs serious capability and isn’t afraid to pay for it at the pump.

City and highway performance

The EPA estimates 15 MPG in the city and 20 MPG on the highway for this Sierra configuration. The city figures reflect how much fuel the engine uses when accelerating from a standstill, navigating stop-and-go traffic, and idling at red lights. The highway number shows what’s possible under ideal conditions when the engine settles into a cruising speed, although the truck’s size and weight work against it. Remember, these numbers reflect ideal conditions. Add in hills, headwinds, or a heavy payload, and expect those figures to drop.

Annual fuel cost

According to the EPA, the estimated annual fuel cost for the 2019 GMC Sierra K10 4WD 6.2L V8 is $3,400. This figure is based on driving 15,000 miles per year and using national average fuel prices. It’s a helpful benchmark, but your actual fuel costs can be affected by local fuel prices, driving habits, and the type of driving you do. If you frequently tow or drive aggressively, you will almost certainly exceed that $3,400 estimate. For a broader look at SIERRA MPG across all years, check out our other model pages.

Real-world expectations

While the EPA provides a good starting point, real-world fuel economy can vary considerably. Some owners of this Sierra report numbers that are close to the EPA estimates, but many see significantly lower numbers, especially in city driving. Aggressive acceleration, short trips with a cold engine, and excessive idling all reduce MPG. The 10-speed automatic transmission prioritizes power and responsiveness, which sometimes affects fuel economy. Towing, of course, will significantly reduce MPG. Expect fuel economy to drop dramatically when hauling heavy loads.

How it compares

The 2019 Sierra’s fuel economy is similar to its competitors. A Ford F-150 with the 5.0L V8 and four-wheel drive manages roughly the same 17 MPG combined. Ram’s 1500 with the 5.7L Hemi V8 and eTorque mild-hybrid system does slightly better, often achieving around 19 MPG combined. The Toyota Tundra, with a less technically advanced but equally thirsty 5.7L V8, generally lags behind the Sierra, closer to 15 MPG combined. These numbers show that fuel economy is very similar in this class of full-size trucks. The Sierra’s appeal is in its styling, technology, and the strong 6.2L V8 engine. If you’re concerned about fuel costs, compare all Gmc fuel economy data.

Tips to maximize efficiency

Take advantage of the Sierra’s driver-selectable modes. When power isn’t a priority, switch to “Normal” or “Eco” mode. These modes adjust throttle response and transmission shift points to prioritize fuel efficiency. They may make the engine less responsive, but the fuel savings can be worthwhile.

Avoid aggressive acceleration and hard braking. The 6.2L V8 is fun, but driving aggressively will increase your fuel bill. Gentle acceleration and anticipating traffic flow will help the engine stay in its most efficient operating range.

Keep your tires properly inflated. Underinflated tires increase rolling resistance, which forces the engine to work harder and burn more fuel. Check your tire pressure regularly and inflate them to the recommended level. This can significantly improve gas mileage.

Consider the weight you’re carrying. Hauling unnecessary tools, equipment, or other items in the bed adds weight and reduces fuel economy. Empty out the bed regularly to improve efficiency. Every pound adds up, so reduce weight where possible.

Minimize idling. Letting the engine idle consumes fuel without covering any distance. If you’re going to be stopped for more than a minute or two, turn off the engine. Modern engines are designed to be restarted frequently without causing damage.