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: Front Passenger Occupant Classification Sensor
Your vehicle is equipped with a front passenger occupant classification sensor
as a part of the supplemental restraint system. This sensor is equipped in the front
passenger's seat cushion. This sensor measures the electrostatic capacity of the
front passenger's seat. The SAS unit is designed ...
Mazda 6 Owners Manual: Base removal
1. Remove the rearview mirror.
2. Wind each end of a wire around a bar.
Warning
Using a SST (piano wire) with bare hands can cause injury. Always
wear gloves when using a SST (piano wire).
Note
Use a long sawing action to spread the work over the whole length
of the SST (piano w ...