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: Immobilizer system reprogram procedure
Note
When an error occurs during the reprogram procedures, except when
the PCM is replaced, repeat the procedure from Step 1. If you still cannot
reprogram, confirm how many keys can start the engine. Then, perform the key
replacement or addition reprogram procedure according to the val ...
Mazda 6 Owners Manual: Tires
For reasons of proper performance, safety, and better fuel economy, always maintain
recommended tire inflation pressures and stay within the recommended load limits
and weight distribution.
WARNING
Using Different Tire Types: Driving your vehicle with different types
of tires is dangerous. I ...