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: Roof molding installation
1. Attach the roof molding to the T stud at the A section.
2. Press in the roof molding along the direction (1) shown in the figure and
attach it to the clip A at the B section.
3. Hook the roof molding to the clip B at the C section, press it in, and
attach the roof molding to the clip B.
...
Mazda 6 Owners Manual: Lights-On Reminder
The lights-on reminder is operable when the time setting*1 of the auto headlight
off function is off.
If lights are on and the ignition is switched to ACC or off, a continuous beep
sound will be heard when the driver's door is opened.
*1 If the light switch is left on, the auto headlight off f ...