1. Remove the air filter.
2. Inspect the air filter.
Note

Air filter removal/installation
A/c unit removal/installationMazda 6 Service Manual: Rear door removal/installation
Warning
Handling the side air bag sensor improperly can accidentally
deploy the side air bag module, which may seriously injure you. Read AIR BAG
SYSTEM SERVICE WARNINGS before working around the B-pillar areas. (See
SERVICE WARNINGS.)
Note
The side air bag sensor is located in t ...
Mazda 6 Service Manual: Pcv valve inspection
1. Disconnect the negative battery cable.
2. Remove the intake maniforld.(see INTAKE-AIR SYSTEM REMOVAL/INSTALLATION.)
3. Remove the PCV valve.
4. Blow through the valve and verify that air flows as specified.
If not as specified, replace the PCV valve.
Specification
...