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: Radiator cap
Warning
Never remove the radiator cap while the engine is running, or when
the engine and radiator are hot. Scalding coolant and steam may shoot out
and cause serious injury. It may also damage the engine and cooling system.
Turn off the engine and wait until it is cool. Even then, be ve ...
Mazda 6 Owners Manual: Drive Selection (Some models)
Drive selection is a system to switch the vehicle's drive mode. When the sport
mode is selected, vehicle's response against accelerator operation is enhanced.
This provides additional quick acceleration which may be needed to safely make maneuvers
such as lane changes, merging onto freeways, o ...