GMC Sierra Classic 2007 Owner's Manual page 489

3. Remove the engine air cleaner/filter from the
housing. Care should be taken not to dislodge
dirt in the air cleaner.
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 button at
the end of the indicator.
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.
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