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: Curtain Air Bags
The curtain air bags are mounted in the front and rear window pillars, and the
roof edge along both sides.
When the air bag crash sensors detect a side impact of greater than moderate
force, the curtain air bag inflates quickly and helps to reduce injury mainly to
the rear outboard passenger' ...
Mazda 6 Owners Manual: Bonnet removal/installation
Warning
Removing the bonnet without supporting can be dangerous. The
bonnet may fall and injure you. Always perform the following procedure with
at least another person.
1. Disconnect the windshield washer hose.
2. To remove the bonnet hinge, remove the front fender panel.
3. To remov ...