2025 GMC Sierra 2WD (3L 6-cyl, Automatic 10-spd, Diesel) MPG & Specs
Quick answer
The 2025 GMC Sierra 2WD gets an EPA-estimated 23/29 MPG (city/highway) and 26 MPG combined, with an estimated $3,050/year fuel cost and 399 g/mi CO₂. Engine: 3 L 6-cyl.
The 2025 GMC Sierra 2WD with the 3-liter 6-cylinder diesel engine returns an EPA-estimated 23 MPG in the city and 29 MPG on the highway, for a combined 26 MPG. This page summarizes the official EPA fuel-economy and emissions data for this configuration.
| Engine | 3 L 6-cyl |
| Transmission | Automatic 10-spd |
| Drive | Rear-Wheel Drive |
| Fuel type | Diesel |
| Vehicle class | Standard Pickup Trucks 2WD |
| MPG — city | 23 |
| MPG — highway | 29 |
| MPG — combined | 26 |
| Annual fuel cost* | $3,050 |
| CO₂ tailpipe | 399 g/mi |
| EPA GHG score | 5/10 |
How efficient is it?
With a combined 26 MPG, the 2025 GMC Sierra 2WD sits in the moderate range for fuel economy. That is about 48% better than the typical Standard Pickup Trucks 2WD of its era (18 MPG class average), making it one of the more efficient choices in its class.
Fuel economy and running costs
At about $3,050 per year in fuel (EPA estimate, 15,000 mi/yr), fuel is a major part of the cost of owning the 2025 GMC Sierra 2WD. Over five years that is roughly $15,250 at today's prices — before insurance, maintenance, and depreciation.
Emissions
The 2025 GMC Sierra 2WD emits approximately 399 grams of CO₂ per mile at the tailpipe, earning an EPA greenhouse-gas score of 5 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.