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: Opening the Hood
1. With the vehicle parked, pull the release handle to unlock the hood.
2. Insert your hand into the hood opening, slide the latch lever to the right,
and lift up the hood.
NOTE
The lever is located a little to the left of center when facing the vehicle.
3. Grasp the support rod in the pad ...
Mazda 6 Owners Manual: Air mix actuator inspection
1. Connect battery positive voltage to terminal D or F and ground to terminal
F or D of the air mix actuator.
2. Verify that the air mix actuator operates as shown below.
If not as specified, replace the air mix actuator.
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3. Verify that the resistance between the terminals of the ...