Fuel filters prevent dirt, rust or debris from contaminating the fuel tank. Every fuel filter needs yearly cleaning as a part of annual car maintenance, according to most mechanics. Vehicle manufacturers disagree; they generally insist that the fuel filter only needs to be cleaned every 50,000 miles or every five years, whichever comes first. Always consult your own car's manufacturer, as each manufacturer has a different opinion on when the filter should be cleaned.
Misfiring During Acceleration
The engine needs a constant flow of fuel in order for combustion to take place. A partially clogged fuel filter can reduce the amount of fuel that gets to the engine and will affect engine performance. Misfiring during acceleration is often the first sign of a small clog in the fuel filter. If you press down on the accelerator, but the car remains at the same RPM and speed, this is a clear indicator of a clog. Also, if the engine makes a sputtering combustion noise when the accelerator is pushed, that is also a sign of a minor clog.
Stalling is often the second sign of a clogged filter. Stopping your car at a stop sign/ stoplight only to have the car shut down and become difficult to restart is a strong indicator of a clogged fuel filter. Your engine may also be sputtering as if it were running out of gas when going uphill or downhill; this, again, is likely because the engine is not getting gas due to a fuel filter clog. Stalling can be inconvenient or even life-threatening and should be prevented.
Hard to Start or Won't start
The last symptom of a clogged fuel injector is an engine that takes multiple attempts to start. If you hear the starter clicking, then you know the starter itself works and isn't the problem. Difficulty starting is the strongest indicator that the fuel filter will soon be fully clogged and will incapacitate your car. If a fuel filter is entirely blocked or clogged, it will prevent fuel from reaching the engine. Engines require the combustion of fuel and air to make their pistons move. If the engine has no fuel, the car cannot start.