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: Abs (abs/tcs) hu/cm system inspection
System Inspection
Preparation
1. Verify that the battery is fully charged. With the ignition switch on,
verify that the ABS and BRAKE system warning lights goes out after 2.4
seconds.
2. If the lights stays on after 2.4 seconds, the ABS (ABS/TCS) HU/CM
detects a failure. Follow the troubles ...
Mazda 6 Owners Manual: Power window motor inspection
Drivers Side
1. Disconnect the power window motor connector.
2. Apply battery positive voltage to the power window motor terminals E and F
and inspect the operation the power window motor operation.
If not as specified, replace the power window motor.
3. Apply battery positive voltage ...