18 MPG combined isn’t going to win any awards, but for a 2018 GMC Sierra 1500 Hybrid 4WD with a 5.3L V8, it’s a compromise. This truck isn’t for those obsessed with MPG; it’s for the buyer who needs the capability: towing, payload, four-wheel drive, but wants to soften the blow at the pump a little. They’re buying a tool, and they’re willing to live with less-than-stellar efficiency to get the job done.

City and highway performance

The EPA estimates of 16 MPG in the city and 21 MPG on the highway reflect the realities of a large displacement engine and a hybrid system playing a supporting role. The electric motor assists during initial acceleration and can provide some regenerative braking benefit in stop-and-go situations, helping to explain the city MPG number. The highway MPG suffers from the inherent aerodynamic challenges of a full-size truck and the engine working to maintain higher speeds. An eight-speed automatic transmission certainly helps to optimize fuel economy, but can only do so much with this powertrain. The SIERRA MPG across all years isn’t a pretty picture for this segment in general.

Annual fuel cost

The EPA estimates an annual fuel cost of $2,450 for the 2018 GMC Sierra 1500 Hybrid 4WD. This calculation is based on driving 15,000 miles per year and uses the national average fuel price at the time of calculation (which typically uses the prevailing price of regular unleaded gasoline). Individual costs will vary depending on driving habits, local fuel prices, and the actual number of miles driven. It’s a useful benchmark, but remember it’s just an estimate.

Real-world expectations

While the EPA provides a standardized testing procedure, real-world fuel economy can vary significantly. Aggressive driving, heavy loads, frequent towing, and even tire pressures can all impact the numbers you see on the dashboard. Expect that 18 MPG combined figure to dip lower if you’re regularly using the Sierra for its intended purpose: hauling materials on a job site, towing a trailer, or navigating challenging terrain. However, conscious driving habits and proper maintenance can push you closer to the EPA’s estimates.

How it compares

Compared to its conventionally powered rivals, the 2018 Sierra Hybrid 1500’s fuel economy lands in a specific spot. A comparable 2018 Ford F-150 4×4 with the 5.0L V8 engine, for example, is EPA-rated at 17 MPG combined. A similarly equipped 2018 Ram 1500 4×4 with the 5.7L Hemi V8 achieves around 15 MPG combined. These small differences are meaningful to some buyers who prioritize fuel cost, but they need to weigh the cost savings against overall capability and purchase price. The buyer shopping all Gmc fuel economy data understands there are no miracles in this segment.

Tips to maximize efficiency

Use the Sierra Hybrid’s electric assist. Gentle acceleration from a stop allows the electric motor to provide the initial torque delivery, reducing the demand on the gasoline engine and saving fuel.

Practice smooth and consistent driving habits. Avoid hard acceleration and braking, as these actions require the engine to work harder and consume more fuel. Anticipate traffic flow and maintain a steady speed whenever possible.

Keep your tires properly inflated. Underinflated tires increase rolling resistance, which reduces fuel economy. Check your tire pressure regularly and inflate them to the recommended level, which is usually found on a sticker inside the driver’s side doorjamb or in the owner’s manual.

Minimize idling. Excessive idling wastes fuel and emits unnecessary pollutants. If you’re stopped for more than a minute, turn off the engine. The hybrid system will automatically restart the engine when needed.

Reduce weight. The heavier your vehicle, the more fuel it consumes. Remove any unnecessary items from the truck bed and cab to reduce weight and improve fuel economy.