1. Remove the clamps and vacuum hose.
2. Apply both suction and pressure to the engine-side hose, and verify that air blows only toward that side.

Air bleeding
Brake pedal inspectionMazda 6 Service Manual: Fuel line pressure inspection
Warning
Fuel line spills and leakage are dangerous. Fuel can ignite and
cause serious injuries or death. Fuel can also irritate skin and eyes. To
prevent this, always complete the BEFORE REPAIR PROCEDURE. (See BEFORE
REPAIR PROCEDURE.)
Caution
Disconnecting/connecting the quick r ...
Mazda 6 Service Manual: Fuel Requirements
Vehicles with catalytic converters or oxygen sensors must use ONLY UNLEADED FUEL,
which will reduce exhaust emissions and keep spark plug fouling to a minimum.
This vehicle will perform best with fuel listed in the table.
* U.S. federal law requires that octane ratings be posted on gasoline st ...