17 MPG combined, a figure many might balk at in today’s economy, is what the 2026 GMC Sierra 2WD with the 5.3L V8 and 10-speed automatic delivers, and it’s a number that perfectly encapsulates the mission of this truck. This isn’t a vehicle striving for class-leading efficiency at every turn; it’s a full-size pickup built for capability, comfort, and the enduring appeal of V8 power. Those who choose this specific configuration of the Sierra are looking for a workhorse that can also ferry the family, tow a decent-sized trailer, and handle daily duties without feeling underpowered. They understand that a 5,000-pound truck with a naturally aspirated V8 isn’t designed to sip fuel, but rather to excel at tasks that demand torque and durability. The 17 MPG represents a pragmatic compromise, a nod to modern efficiency standards without sacrificing the core attributes that define a GMC Sierra.

City and highway performance

Breaking down that combined figure, the 2026 GMC Sierra 2WD achieves 16 MPG in the city and 20 MPG on the highway. The city number is fairly conventional for a half-ton truck with this powertrain. Stop-and-go traffic, the enemy of any large internal combustion engine, will see the 5.3L V8 working harder, but the 10-speed automatic transmission does an admirable job of keeping revs low and accessing the engine’s broad torque band efficiently. On the open road, the 20 MPG Highway rating is where the Sierra truly settles in. The taller gears of the 10-speed allow the engine to loaf at highway speeds, and cylinder deactivation technology, a hallmark of GM’s V8s, further contributes to that more respectable figure. Drivers who frequently log highway miles for commutes or road trips will appreciate this aspect, as the truck becomes noticeably more economical when freed from the constant demands of urban driving.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2026 GMC Sierra 2WD 5.3L 8-cyl to be exactly $2,600 per year. This figure is calculated based on an average of 15,000 miles driven annually and using national average fuel prices, which the EPA updates regularly. For a potential buyer, this $2,600 estimate provides a tangible, real-world cost projection beyond just the MPG numbers. It’s a direct financial indicator of what maintaining this vehicle will entail in terms of fuel expenses over a year. Understanding this makes the decision transparent, acknowledging that while the Sierra offers significant utility and performance, it also comes with a predictable, higher annual fuel budget compared to smaller, more efficient vehicles. This is a cost most Sierra owners are willing to bear, as the utility and capability the truck provides vastly outweigh the fuel cost implications for their specific needs.

Real-world expectations

In the real world, Sierra owners will find the 17 MPG combined to be a more-than-achievable target, provided they drive judiciously. This truck isn’t designed for lead-footed acceleration or aggressive maneuvers. Its character is one of measured power delivery and confident cruising. Expecting to consistently hit the 20 MPG highway mark means maintaining speed limits, using cruise control, and avoiding rapid changes in throttle. Similarly, the 16 MPG city figure is realistic for drivers who anticipate acceleration and braking, using the truck’s momentum rather than fighting against it. Towing, of course, will significantly impact these numbers. Hauling a 5,000-pound boat or trailer will drop fuel economy considerably, often into the low teens or even single digits, a fact any experienced truck owner understands and budgets for. This 5.3L V8 is a known quantity for its reliability and capability, accepting that its thirst is part of its working ethos.

How it compares

The 2026 GMC Sierra 2WD with the 5.3L V8 finds itself in a highly competitive segment, and its 17 MPG combined is right in line with its primary rivals. A comparable 2026 Ford F-150 with the 5.0L V8 and 10-speed automatic typically achieves 18 MPG combined (17 City / 23 Highway) on its 2WD configuration, a slight edge on the highway. The 2026 Ram 1500 with the 5.7L HEMI V8 and 8-speed automatic also usually comes in at 17 MPG combined (15 City / 22 Highway) for its 2WD models, with a slightly better highway figure too. What becomes clear is that if V8 power is the priority, the fuel economy figures are almost universally similar across these domestic trucks. Buyers are choosing between ecosystems, GM’s, Ford’s, or Ram’s, rather than chasing a significant MPG advantage. The Sierra’s distinct GMC styling, interior material quality, and specific trim offerings often become the deciding factors for owners, not a single additional MPG point. For those prioritizing efficiency in a full-size truck, options like the Ford F-150 PowerBoost hybrid (25 MPG combined for 2WD) or the Ram 1500 with the 3.6L Pentastar V6 and eTorque (23 MPG combined for 2WD) present alternatives, but they represent a different character and cost structure. For all GMC fuel economy data, and specifically to see SIERRA MPG across all years, our database offers detailed figures.

Tips to maximize efficiency

Given the Sierra’s substantial weight and V8 engine, maintaining consistent throttle input is key. Avoid aggressive acceleration and decelerations; instead, smoothly build speed and anticipate stops to coast whenever safe and practical. The 10-speed automatic is designed to find the optimal gear, but your driving style directly influences its efficiency.

Regular vehicle maintenance plays a crucial role. Ensuring proper tire inflation to the manufacturer’s recommended pressures, clean air filters, and routine oil changes means the engine doesn’t have to work harder than necessary. This attention to detail can collectively add up to measurable fuel savings.

Minimize unnecessary weight. While the Sierra is designed to haul, carrying around tools, equipment, or other heavy items not actively being used will incrementally reduce fuel economy. Remove anything that doesn’t need to be in the bed or cab, as every extra pound costs fuel.

Use the cruise control on highway stretches. Maintaining a steady speed not only makes for a more relaxed drive but also prevents the subtle speed fluctuations that often lead to decreased efficiency. The 5.3L V8 benefits greatly from consistent, lower RPM operation.

Consider the use of tonneau covers. While the aerodynamic benefits can be debated for trucks, a well-fitted tonneau cover can reduce drag, particularly at higher speeds, contributing to marginal gains in highway fuel economy. Every minor improvement can help the truck achieve its best possible efficiency.