Based on data from 20 vehicles, 3,025 fuel-ups and 815,165 miles of driving, the 2012 GMC Sierra gets a combined Avg MPG of 13.78 with a 0.12 MPG margin of error.

Any Engine Type 5.3L V8 FLEX (1) 5.3L V8 GAS (14) 6.2L V8 FLEX (2) 6.2L V8 GAS (3) Any Body Style Crew Cab Pickup (1) Any Submodel Denali (5) Base (15)

Below you can see a distribution of the fuel-ups with 93 outliers (2.98%) removed.

Following shows the average MPG of each of the 20 vehicles in the system.

• Denali

  2012 GMC Sierra Denali 6.2L V8 FLEX Automatic 6 Speed
  Added Oct 2016 • 555 Fuel-ups

  Property of bmhlondon

• 13.6 Avg MPG

• Sierra

  2012 GMC Sierra Denali 6.2L V8 GAS Automatic 6 Speed
  Added Mar 2017 • 683 Fuel-ups

  Property of panther5232

• 12.7 Avg MPG

• GMC truck

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed
  Added Aug 2016 • 334 Fuel-ups

  Property of recoutts

• 17.8 Avg MPG

• Sierra

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed
  Added Sep 2016 • 339 Fuel-ups

  Property of mmlipps

• 16.5 Avg MPG

• 2012 GMC Truck

  2012 GMC Sierra Denali 6.2L V8 FLEX Automatic 6 Speed
  Added Mar 2017 • 354 Fuel-ups

  Property of xdiehard04x

• 12.5 Avg MPG

• Doye

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed
  Added Aug 2016 • 131 Fuel-ups

  Property of pkking

• 16.4 Avg MPG

• Sold Net's GMC 2012 truck

  2012 GMC Sierra 5.3L V8 FLEX Automatic 6 Speed
  Added Mar 2017 • 22 Fuel-ups

  Property of redrover58

• 17.9 Avg MPG

• SAWYER

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed Crew Cab Pickup
  Added Mar 2019 • 6 Fuel-ups

  Property of ChumLeeAFM

• 18.5 Avg MPG

• My Sierra

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed
  Added Jul 2017 • 46 Fuel-ups

  Property of justinschopp

• 15.7 Avg MPG

• Gmc sierra farm fuel

  2012 GMC Sierra Denali 6.2L V8 GAS Automatic 6 Speed
  Added Mar 2017 • 263 Fuel-ups

  Property of sask

• 12.3 Avg MPG

• Scott's Truck

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed
  Added Mar 2017 • 206 Fuel-ups

  Property of scargis

• 17.4 Avg MPG

• My Sierra

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed
  Added Jan 2018 • 7 Fuel-ups

  Property of Donnab11257

• 15.5 Avg MPG

• GMC Sierra

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed
  Added Aug 2016 • 145 Fuel-ups

  Property of 2012GMCLL

• 18.9 Avg MPG

• Lyle

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed
  Added Mar 2017 • 180 Fuel-ups

  Property of LyleO

• 14.3 Avg MPG

• Blue Bird

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed
  Added Mar 2017 • 61 Fuel-ups

  Property of jlewis

• 11.7 Avg MPG

• 2012 GMC Sierra 1500

  2012 GMC Sierra Denali 6.2L V8 GAS Automatic 6 Speed
  Added Mar 2017 • 21 Fuel-ups

  Property of sask

• 13.9 Avg MPG

• My Sierra

  2012 GMC Sierra 5.3L GAS V8 Automatic 6
  Added Jun 2015 • 7 Fuel-ups

  Property of Norgaards1

• 13.7 Avg MPG

• Sierra

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed
  Added Apr 2017 • 32 Fuel-ups

  Property of Canper_Bob

• 14.0 Avg MPG

• COBRA

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed
  Added Jun 2020 • 8 Fuel-ups

  Property of jake8702

• 13.5 Avg MPG

• Sierra

  2012 GMC Sierra 5.3L V8 GAS Automatic 6 Speed
  Added Mar 2018 • 15 Fuel-ups

  Property of bbrinks81

• 17.3 Avg MPG