Based on data from 66 vehicles, 5,132 fuel-ups and 1,917,659 miles of driving, the 2018 GMC Sierra 2500 HD gets a combined Avg MPG of 14.47 with a 0.11 MPG margin of error.

Any Engine Type 6.0L V8 FLEX (9) 6.6L V8 DIESEL (57) Any Body Style Extended Cab Pickup (2) Crew Cab Pickup (19) Any Submodel Base (2) SLE (3) SLT (24) Denali (37)

Below you can see a distribution of the fuel-ups with 156 outliers (2.95%) removed.

Following shows the average MPG of each of the 66 vehicles in the system.

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• Sierra 2500 HD

  2018 GMC Sierra 2500 HD SLT 6.0L V8 FLEX Automatic 6 Speed
  Added May 2019 • 184 Fuel-ups

  Property of larboy

• 13.3 Avg MPG

• My Sierra 2500 HD

  2018 GMC Sierra 2500 HD SLT 6.6L V8 DIESEL Automatic 6 Speed
  Added Mar 2023 • 93 Fuel-ups

  Property of RandD

• 14.4 Avg MPG

• 18 Sierra

  2018 GMC Sierra 2500 HD SLT 6.6L V8 DIESEL Automatic 6 Speed Crew Cab Pickup
  Added Jan 2022 • 298 Fuel-ups

  Property of texags06

• 14.1 Avg MPG

• Denali 2500HD

  2018 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 6 Speed
  Added Jan 2018 • 151 Fuel-ups

  Property of Mavis500

• 15.4 Avg MPG

• My Sierra 2500 HD

  2018 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 6 Speed
  Added Nov 2023 • 34 Fuel-ups

  Property of cmlouis

• 14.0 Avg MPG

• 18 Duramax

  2018 GMC Sierra 2500 HD SLT 6.6L V8 DIESEL Automatic 6 Speed Crew Cab Pickup
  Added Oct 2023 • 30 Fuel-ups

  Property of peterd55

• 16.8 Avg MPG

• My Sierra 2500 HD

  2018 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 6 Speed
  Added Nov 2023 • 10 Fuel-ups

  Property of Whistle

• 15.0 Avg MPG

• My Sierra 2500 HD

  2018 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 6 Speed
  Added May 2018 • 237 Fuel-ups

  Property of jtw811

• 14.4 Avg MPG

• GMC AT HD

  2018 GMC Sierra 2500 HD SLT 6.6L V8 DIESEL Automatic 6 Speed
  Added Jan 2023 • 33 Fuel-ups

  Property of jheen

• 14.5 Avg MPG

• My Sierra 2500 HD

  2018 GMC Sierra 2500 HD SLT 6.0L V8 FLEX Automatic 6 Speed
  Added Mar 2025 • 3 Fuel-ups

  Property of Braba006

• 12.3 Avg MPG

• GMC

  2018 GMC Sierra 2500 HD SLT 6.6L V8 DIESEL Automatic 6 Speed Crew Cab Pickup
  Added Feb 2021 • 174 Fuel-ups

  Property of csundell

• 14.0 Avg MPG

• Sierra 2500

  2018 GMC Sierra 2500 HD SLT 6.6L V8 DIESEL Automatic 6 Speed Crew Cab Pickup
  Added Nov 2018 • 396 Fuel-ups

  Property of IPAGuy

• 12.1 Avg MPG

• Denali

  2018 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 6 Speed
  Added Nov 2017 • 284 Fuel-ups

  Property of superflymtber

• 17.1 Avg MPG

• My Sierra 2500 HD

  2018 GMC Sierra 2500 HD SLT 6.6L V8 DIESEL Automatic 6 Speed
  Added Apr 2019 • 310 Fuel-ups

  Property of 4gkids

• 14.4 Avg MPG

• Robin's Truck

  2018 GMC Sierra 2500 HD SLE 6.6L V8 DIESEL Automatic 6 Speed Crew Cab Pickup
  Added Mar 2021 • 130 Fuel-ups

  Property of Cruiser60

• 14.2 Avg MPG

• 18 Denali HD

  2018 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 6 Speed
  Added May 2024 • 30 Fuel-ups

  Property of AeroTerp

• 12.1 Avg MPG

• My Sierra 2500 HD

  2018 GMC Sierra 2500 HD SLT 6.6L V8 DIESEL Automatic 6 Speed
  Added Nov 2018 • 166 Fuel-ups

  Property of cfort

• 14.7 Avg MPG

• My Sierra 2500 HD

  2018 GMC Sierra 2500 HD SLT 6.0L V8 FLEX Automatic 6 Speed
  Added Dec 2024 • 20 Fuel-ups

  Property of bugaboots

• 10.7 Avg MPG

• Sierra Denali 2500 HD

  2018 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 6 Speed
  Added Mar 2019 • 146 Fuel-ups

  Property of west27

• 13.7 Avg MPG

• 2018 Duramax

  2018 GMC Sierra 2500 HD SLT 6.6L V8 DIESEL Automatic 6 Speed Extended Cab Pickup
  Added Nov 2017 • 148 Fuel-ups

  Property of Rocketrollinsx

• 14.4 Avg MPG

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