2006 GMC Sierra Trucks - 2WD
- 6 cylinder, 5-speed manual, 16 city / 22 highway
- 6-cylinder, 4.3L, 4-speed automatic, 16 city / 21 highway
- Sierra Hybrid, 8 cylinder, 5.3L, 4-speed automatic, 18 city / 21 highway
- 8 cylinder, 4.8L, 5-speed manual, 16 city / 21 highway
- 8 cylinder, 4.8L, 4-speed automatic, 16 city / 21 highway
- 8 cylinder, 5.3L, 4-speed automatic, 16 city / 20 highway
- 8 cylinder, 5.3L, 4-speed automatic, FLEX-FUEL
- Gasoline: 16 city / 20 highway
- E85: 12 city / 16 highway
- 8 cylinder, 6L, 4-speed automatic, Premium gas, 14 city / 19 highway
2006 GMC Sierra Trucks - 4WD
- 6 cylinder, 4.3L, 5-speed manual, 15 city / 20 highway
- 6 cylinder, 4.3L, 4-speed automatic, 15 city / 18 highway
- Sierra Hybrid, 8 cylinder, 5.3L, 4-speed automatic, 17 city, 19 highway
- 8 cylinder, 4.8L, 5-speed manual, 15 city / 19 highway
- 8 cylinder, 4.8L, 4-speed automatic, 15 city / 19 highway
- 8 cylinder, 5.3L, 4-speed automatic, 15 city / 19 highway
- 8 cylinder, 5.3L, 4-speed automatic, FLEX-FUEL
- Gasoline: 15 city / 19 highway
- E85: 11 city / 14 highway
- 8 cylinder, 6L, 4-speed automatic, Premium gas, 14 city / 17 highway
2006 GMC Sierra Trucks - AWD
- 8 cylinder, 6L, 4-speed automatic, Premium gas, 13 city / 17 highway
GMC recommends regular gas for all Sierra trucks unless noted otherwise.

