2026 GMC Sierra 4WD with Sport Mode (5.3L 8-cyl) MPG & Specs
Quick answer
The 2026 GMC Sierra 4WD with Sport Mode gets an EPA-estimated 15/19 MPG (city/highway) and 17 MPG combined, with an estimated $3,600/year fuel cost and 522 g/mi CO₂. Engine: 5.3 L 8-cyl.
The 2026 GMC Sierra 4WD with Sport Mode with the 5.3-liter 8-cylinder regular gasoline engine returns an EPA-estimated 15 MPG in the city and 19 MPG on the highway, for a combined 17 MPG. This page summarizes the official EPA fuel-economy and emissions data for this configuration.
| Engine | 5.3 L 8-cyl |
| Transmission | Automatic 10-spd |
| Drive | 4-Wheel Drive |
| Fuel type | Regular Gasoline |
| Vehicle class | Standard Pickup Trucks 4WD |
| MPG — city | 15 |
| MPG — highway | 19 |
| MPG — combined | 17 |
| Annual fuel cost* | $3,600 |
| CO₂ tailpipe | 522 g/mi |
| EPA GHG score | 3/10 |
How efficient is it?
With a combined 17 MPG, the 2026 GMC Sierra 4WD with Sport Mode sits in the low range for fuel economy. That is roughly 20% thirstier than the typical Standard Pickup Trucks 4WD of its era (21 MPG class average) — expect higher fuel bills than class-average alternatives.
Fuel economy and running costs
At about $3,600 per year in fuel (EPA estimate, 15,000 mi/yr), fuel is a major part of the cost of owning the 2026 GMC Sierra 4WD with Sport Mode. Over five years that is roughly $18,000 at today's prices — before insurance, maintenance, and depreciation.
Emissions
The 2026 GMC Sierra 4WD with Sport Mode emits approximately 522 grams of CO₂ per mile at the tailpipe, earning an EPA greenhouse-gas score of 3 out of 10. Lower emissions generally track higher fuel economy.
How to read these numbers
EPA figures come from standardized laboratory test cycles and are the same estimates shown on the vehicle's window sticker. Your real-world mileage depends on driving style, conditions, fuel grade, and maintenance. Use combined MPG and annual fuel cost to compare vehicles fairly.