Whether you’ve got a Diesel or gas vehicle, keeping the Fuel system clean is a critical step to retaining the peak performance your vehicle had when it was newer.   Typically when we talk about the fuel system, we’re talking specifically about the fuel injection system. This system is made up of “low-pressure side” and “high-pressure side” components.   Working together, the system functions to deliver the fuel from the tank into the combustion chamber where it can be combusted to do what it needs to do.