Owners of the 2019 GMC Sierra K10 4WD with the 4.3L V6 get 17 MPG combined. This truck isn’t a Prius, and doesn’t try to be. It caters to buyers who value capability and utility over fuel efficiency, owners who need a dependable workhorse capable of hauling materials, navigating job sites, and enduring tough conditions. Fuel economy, while a factor, is often secondary to the truck’s main purpose.

City and highway performance

The EPA estimates suggest 15 MPG in city driving and 20 MPG on the highway. This difference isn’t surprising. The 4.3L V6 requires decent throttle to get moving in stop-and-go traffic, impacting city fuel consumption. However, on the open road, the engine can settle into a more efficient cruising speed, achieving a more palatable 20 MPG on the highway. The durable 6-speed automatic transmission doesn’t offer the gear ratios of newer transmissions, which also affects overall efficiency. Newer transmissions help hold the engine in its sweet spot for fuel economy. The Sierra K10’s traditional four-wheel-drive system benefits off-road situations and adverse weather, but also contributes to a slightly lower MPG compared to its two-wheel-drive counterparts.

Annual fuel cost

The EPA estimates an annual fuel cost of $2,600 for this configuration of the 2019 GMC Sierra. This figure is based on driving 15,000 miles per year and national average fuel prices. It’s a useful benchmark for comparing running costs with other vehicles, but individual fuel expenses will vary. Factors like driving habits, regional fuel prices, and the type of driving (mostly city or highway) all play a significant role in determining how much you’ll actually spend at the pump. Consider it a starting point, not a definitive number.

Real-world expectations

While EPA estimates provide a standardized comparison, real-world MPG figures will always fluctuate. Don’t be surprised to see slightly lower numbers, especially if you frequently use four-wheel drive, tow trailers, or carry heavy loads. Aggressive driving, including rapid acceleration and hard braking, will also negatively impact your fuel economy. Conversely, if you focus on smooth acceleration, maintain consistent speeds, and minimize idling, you might approach or slightly exceed the EPA estimates. Owner forums and online communities for the Sierra are great resources for gathering real-world MPG data from other drivers.

How it compares

Compared to other full-size, four-wheel-drive trucks of the era, the 2019 GMC Sierra K10 4WD with the 4.3L V6 is in the middle of the pack for fuel economy. For example, a similar-year Ford F-150 with its base 3.3L V6 offered similar MPG numbers, around 16 MPG combined in 4×4 configuration. A Ram 1500 with the 3.6L V6 could achieve slightly better numbers, hovering around 18-19 MPG combined, largely due to its mild-hybrid eTorque system assisting the engine. These differences might seem minor, but they can add up over the lifespan of the vehicle. Comparing SIERRA MPG across all years can provide further context.

More powerful engine options in the Sierra, such as the 5.3L and 6.2L V8s, will deliver lower fuel economy, typically in the 14-16 MPG combined range. The V8s offer more horsepower and torque, but buyers concerned about fuel economy might find the 4.3L V6 a reasonable compromise. Those needing even better fuel efficiency may want to consider smaller trucks or even checking on all Gmc fuel economy data.

Tips to maximize efficiency

Regular maintenance is key. Ensure your tires are properly inflated, as underinflated tires increase rolling resistance and reduce fuel economy. Keep up with scheduled oil changes and air filter replacements. A clean air filter allows the engine to breathe more easily, optimizing combustion and improving efficiency.

Drive conservatively. Avoid aggressive acceleration and hard braking. Anticipate traffic flow and maintain a consistent speed whenever possible. Using cruise control on the highway can help prevent speed variations that waste fuel.

Minimize idling. If you anticipate being stopped for more than a minute or two, turn off the engine. Excessive idling consumes fuel without covering any distance, especially in colder weather, when the engine takes longer to reach its optimal operating temperature.

Consider removing unnecessary weight from the truck bed. Extra weight increases fuel consumption, so eliminate any cargo that isn’t essential. Small amounts of added weight can cumulatively affect your MPG over time.

Plan your trips strategically. Combine multiple errands into a single trip to reduce cold starts, which are less fuel-efficient. Avoid driving during peak traffic hours, as stop-and-go congestion lowers MPG.