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 station pumps.
Fuel with a rating lower than 87 octane (91 RON) will negatively affect the emission control system performance and could also cause engine knocking and serious engine damage.
CAUTION
Leaded fuel is harmful to the catalytic converter and oxygen sensors and will lead to deterioration of the emission control system and or failures.
Gasoline blended with oxygenates such as alcohol or ether compounds are generally referred to as oxygenated fuels. The common gasoline blend that can be used with your vehicle is ethanol blended at no more than 10 %. Gasoline containing alcohol, such as ethanol or methanol, may be marketed under the name "Gasohol".
Vehicle damage and drivability problems resulting from the use of the following may not be covered by the warranty.
Emission Control SystemMazda 6 Owners Manual: Door lock timer unit inspection
1. Measure the voltage at the door lock timer unit terminals (other than
terminal 1E and 2W) as indicated below.
If not as specified, inspect the parts listed under Action.
2. Disconnect the negative battery cable.
3. Disconnect the door lock timer unit connector and inspect for continuity ...
Mazda 6 Owners Manual: Power steering fluid inspection
Fluid Level Inspection
1. Inspect the power steering fluid level.
Add fluid to the specified level as necessary.
Fluid specification
ATF M-III or equivalent (e.g. Dexron®II)
Fluid Leakage Inspection
1. Start the engine and let it idle.
2. Turn the steering wheel fully to the left and ...