2027 Chevy Silverado MPG Ratings Drop: What Truck Buyers Need to Know

New 2027 Silverado Models Show Lower Fuel Economy Than Previous Generation

General Motors has officially released fuel economy ratings for the 2027 Chevrolet Silverado 1500 and GMC Sierra 1500, and the numbers reveal a meaningful shift in what buyers can expect at the pump. The new sixth-generation trucks, powered by redesigned 5.7-liter and 6.6-liter V8 engines along with an available 3.0-liter Duramax diesel, deliver measurably lower miles per gallon across multiple configurations compared to their 2026 counterparts.

For shoppers considering the standard Silverado 1500 in rear-wheel drive, the change is particularly noticeable. The 2026 model with a 5.3-liter V8 achieved 16 city, 21 highway, and 18 combined MPG. The new 2027 version with the larger 5.7-liter engine delivers 15 city, 19 highway, and 17 combined, representing a 2-MPG decline on the highway despite offering 47 additional horsepower. This trade-off signals that raw power gains have come at a fuel efficiency cost.

The story grows more significant for off-road focused buyers. The 2027 Silverado 1500 ZR2 with its 6.6-liter V8 four-wheel drive system is rated at 13 city, 15 highway, and 14 combined MPG, compared to the 2026 ZR2’s 14 city, 17 highway, and 15 combined. That represents a 2-MPG drop in highway efficiency, though the new model produces 61 additional horsepower and rides on larger 35-inch all-terrain tires that many off-road buyers actively prefer.

Why Did Fuel Economy Ratings Decrease?

General Motors addressed the efficiency decline directly, explaining that the lower numbers reflect how customers actually configure their trucks rather than bare-bones test vehicles. The company notes that new models now account for popular customer choices like lifted suspensions and larger tire packages when calculating official EPA ratings. Previous generations were tested with standard ride height and factory tires, creating an artificial advantage in fuel economy comparisons.

The automaker also emphasized that its new engine technologies, including higher compression ratios, dual fuel delivery systems, Dynamic Fuel Management, and advanced thermal management, were designed to improve real-world performance even if EPA ratings appear lower. These systems help trucks deliver better drivability and efficiency under actual driving conditions rather than laboratory test cycles.

The Diesel Option Remains Competitive but Takes a Hit

The 3.0-liter Duramax turbo-diesel continues as the most efficient engine choice in the Silverado lineup, achieving 27 MPG highway and 24 MPG combined with over 900 miles of available highway range per tank. However, even the diesel shows softness compared to 2026 models, with ratings down approximately 1 MPG across the board. Despite this decline, GM maintains that the Duramax delivers segment-leading efficiency for buyers who prioritize fuel savings and towing capacity.

Shoppers should note that the base 2.7-liter TurboMax four-cylinder engine ratings are not yet available, as this powertrain will join the lineup in early 2027 following a delayed introduction. When available, this engine should provide a more efficient option for buyers prioritizing fuel economy over maximum capability.

How Does This Compare to Competitors?

When positioned against direct competitors, the 2027 Silverado’s efficiency ratings fall behind comparable models. The Ram 1500 RHO with its 540-horsepower twin-turbocharged inline-six achieves 14 city, 16 highway, and 15 combined MPG. The Ford F-150 Raptor, powered by a 450-horsepower turbocharged V6, reaches 14 city, 18 highway, and 16 combined. Both of these high-performance rivals deliver superior highway fuel economy, giving shoppers something to consider when comparing trucks in this class.

What This Means for Your Purchase Decision

The 2027 Silverado generation represents a more capable and equipped truck than its predecessor, featuring improved technology, refinement, and safety systems. The new Silverado engine updates deliver substantially more standard content and capability, which partially explains the efficiency trade-offs. Buyers should recognize that the lower MPG ratings are intentional, reflecting how modern customers actually configure and use full-size trucks.

If maximizing fuel economy is your primary concern, the Duramax diesel remains the best choice despite its modest efficiency decline. For conventional gasoline buyers, the new engines offer meaningfully more power and technology, so the reduced efficiency may be acceptable depending on your towing needs and driving patterns. The 2027 Silverado production changes also reflect GM’s strategic shift toward more capable configurations, which naturally impacts fuel economy metrics.

When shopping for a 2027 Silverado, factor these official EPA ratings into your total cost of ownership calculations, especially if you drive primarily on highways where the efficiency gap becomes most apparent. Compare your typical fuel costs across the gasoline and diesel options before making your final decision, as the choice could significantly impact your long-term vehicle expenses.