2018 GMC Sierra
The EPA lists 14 versions of the 2018 GMC Sierra. Combined fuel economy ranges from 17 to 20 MPG; the most efficient version is rated 18 city / 24 highway.
At a glance
- Fuel economy
- 17 to 20 MPG combined
Sources: NHTSA complaints, recalls and 5-Star ratings; U.S. EPA
Fuel economy
The EPA lists 14 versions of the 2018 GMC Sierra. Combined fuel economy ranges from 17 to 20 MPG; the most efficient version is rated 18 city / 24 highway.