Cadillac 1999 DeVille Owner's Manual page 286

Engine Air Cleaner/Filter
The engine air cleaner/filter is located next to the
windshield washer fluid reservoir on the driver's side of
the engine. Be sure the engine has cooled before
following these steps to replace the air cleaner filter:
6-16
3. Disconnect the air duct from the mass airflow sensor.
1. Disconnect the Intake
Air Temperature (IAT)
sensor from the base of
the air cleaner.
2. With a screwdriver,
loosen the air duct
clamp, which is located
at the mass airflow
sensor end of the
air duct.
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