The fuel filter is found along the fuel lines, either in the engine compartment or underneath the vehicle by the fuel tank. The job of the fuel filter is to trap any large foreign particles in the fuel and stop them from getting into the engine. With the force of the fast up-and-down motion of the pistons (which compress the air-fuel mixture so it will burn more efficiently), if any large particles manage to get in the fuel, this could cause some serious damage to the engine. So, maintaining a clean fuel filter is important to the performance of a vehicle’s engine.
Replacing the fuel filter periodically (every year or so) for preventative maintenance can reduce the risk of filter-related driveability problems; by the time a vehicle is six or seven years old, there can be a fair amount of rust and debris in the fuel tank. Rust can be formed by moisture and condensation, and debris can get into your tank anytime you add fuel. So changing it on a periodic basis can help minimize the risk of plugging. Most vehicle manufacturers, however, no longer specify a replacement interval for the fuel filter. Or, if they do it’s some incredibly long interval like once every five years or 50,000 miles. Many mechanics feel this is unrealistic and waiting that long to change the filter is asking for trouble.
It is recommended by some mechanics that you should change your fuel filter once a year. But, to be on the safe side you should definitely do it at least every two years. However, if you live in a high-pollution area, or if you drive your vehicle more than the average person, then it will need more attention.