MPG Surprise! Can The 2020 GMC Sierra 3.0L Diesel REALLY Get Up To 30 MPG In The Real World? VIEWS: 420 2020 GMC Sierra 3.0L Diesel We hit the road for a 100-mile loop to find out exactly how efficient the 2020 GMC Sierra new 3.0-liter diesel can be. 2020 GMC Sierra 3.0L Diesel Gallery
