There is a Mazda fuel injector for each of the cylinders in your engine. Each one must be delivering the same amount of fuel on time and in a uniform atomized consistency so combustion will be efficient. In order to ensure this delivery of the fuel to the combustion chamber is consistent, the fuel injectors themselves must be cleaned. The most critical aspect the Mazda owner should know when it pertains to the fuel injectors and the rest of the system is the higher level of cleanliness the fuel must be when it is being delivered to the combustion chamber. This is why the regular replacement of the fuel filter is emphasized by the manufacturer. The Mazda owner can help keep the fuel injectors clean by being careful of just what they place in the fuel tank. The cheapest gas is also generally the dirtiest. By changing the fuel source on a constant basis so the lowest price can be paid, the fuel injectors are potentially subjected to different kinds of contaminants. So, to help keep the fuel injectors as clean as possible, one type of fuel from a particular source should be used as often as possible. The use of a fuel injector cleaner is also now a recommendation so the inside of the injectors are kept in proper working order. Depending on the level of cleanliness of the fuel source you are using for your Mazda, a bottle of this cleaner should be added every 5 to 10 tanks of fuel that are used. Keeping the Mazda fuel injectors clean is the responsibility of the owner. It does not have to be done, but dirty injectors cannot deliver a consistent spray of fuel so the engine will not be able to operate at expected levels.