2008 GMC Sierra 1500 Pickup Owner's Manual - Page 331

{CAUTION: Operating the engine with the air cleaner/filter off can cause you or others to be burned. The air cleaner not only cleans the air; it helps to stop flames if the engine backfires. If it is not there and the engine backfires, you could be burned. Do not drive with it off, and be careful working on the engine with the air cleaner/filter off. 3. Remove the engine air cleaner/filter from the housing. Care should be taken to dislodge as little dirt as possible. 4. Clean the engine air cleaner/filter sealing surfaces and the housing. 5. Inspect or replace the engine air cleaner/filter. 6. Reinstall the cover and tighten the screws. 7. Reset the air filter restriction indicator, if the vehicle has one, by pressing the top button on the indicator. 5-19