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: Dehumidifying (With air conditioner)
Operate the air conditioner in cool or cold weather to help defog the windshield
and side windows.
1. Set the mode selector dial to the desired position.
2. Set the air intake selector to the outside air position (indicator light turns
off).
3. Set the temperature control dial to the desired ...
Mazda 6 Owners Manual: Declaration of Conformity
Keyless Entry System/Immobilizer System
Blind Spot Monitoring (BSM) System
NOTE
During printing time of this user manual the approvals listed above are granted.
WARNING
Change or modifications not expressively approved by the party responsible
for compliance could void the use's authori ...