Based on data from 63 vehicles, 3,510 fuel-ups and 1,123,891 miles of driving, the 2021 GMC Sierra 2500 HD gets a combined Avg MPG of 13.16 with a 0.13 MPG margin of error.

Any Engine Type 6.6L V8 DIESEL (45) 6.6L V8 GAS (17) Any Body Style Extended Cab Pickup (1) Crew Cab Pickup (14) Any Submodel Base (2) SLE (6) SLT (7) AT4 (21) Denali (27)

Below you can see a distribution of the fuel-ups with 11 outliers (0.31%) removed.

Following shows the average MPG of each of the 63 vehicles in the system.

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• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed
  Added Oct 2022 • 18 Fuel-ups

  Property of 656mike

• 12.8 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD SLT 6.6L V8 GAS Automatic 6 Speed
  Added Jul 2021 • 88 Fuel-ups

  Property of scottshon

• 11.9 Avg MPG

• Black GMC Truck

  2021 GMC Sierra 2500 HD SLE 6.6L V8 GAS Automatic 6 Speed Extended Cab Pickup
  Added May 2021 • 32 Fuel-ups

  Property of Zeak1

• 14.1 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Apr 2021 • 14 Fuel-ups

  Property of jtrenaryf350

• 16.0 Avg MPG

• SIERRA 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Nov 2020 • 27 Fuel-ups

  Property of c00permj

• 14.3 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed
  Added Mar 2021 • 87 Fuel-ups

  Property of penaf71

• 11.1 Avg MPG

• AT4

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Jul 2022 • 5 Fuel-ups

  Property of Bluerock1

• 11.1 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD SLT 6.6L V8 GAS Automatic 6 Speed
  Added Mar 2021 • 14 Fuel-ups

  Property of Gordy86

• 14.3 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed
  Added Mar 2022 • 4 Fuel-ups

  Property of tgutwein

• 15.7 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Sep 2021 • 32 Fuel-ups

  Property of anon1234

• 15.5 Avg MPG

• 2021 AT4

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Jan 2021 • 51 Fuel-ups

  Property of TGriffi1

• 16.1 Avg MPG

• 2021 GMC

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed
  Added Mar 2021 • 68 Fuel-ups

  Property of tishma09

• 9.8 Avg MPG

• 2021 Sierra 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Jan 2021 • 33 Fuel-ups

  Property of SoundLineDesign

• 14.6 Avg MPG

• 2021 GMC Sierra 2500 Denali

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Feb 2021 • 15 Fuel-ups

  Property of WydOpen

• 15.2 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Feb 2021 • 31 Fuel-ups

  Property of whytebeast

• 12.9 Avg MPG

• Paul’s Sierra 2500 AT4

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed
  Added May 2021 • 16 Fuel-ups

  Property of Pboerschlein

• 15.8 Avg MPG

• Black Betty

  2021 GMC Sierra 2500 HD SLT 6.6L V8 GAS Automatic 6 Speed
  Added Jan 2021 • 26 Fuel-ups

  Property of nickgray17

• 13.6 Avg MPG

• My Sierra 2500 HD

  2021 GMC Sierra 2500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Dec 2020 • 11 Fuel-ups

  Property of duraron

• 13.4 Avg MPG

• GMC Sierra 2500 HD

  2021 GMC Sierra 2500 HD SLE 6.6L V8 GAS Automatic 6 Speed Crew Cab Pickup
  Added Mar 2021 • 12 Fuel-ups

  Property of 85burban

• 11.7 Avg MPG

• AT4

  2021 GMC Sierra 2500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed
  Added Feb 2021 • 44 Fuel-ups

  Property of powell1983

• 12.9 Avg MPG

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