Some common clogged fuel filter symptoms include problems starting the car, engine hesitation and engine stalling during operation. Erratic performance and rough operation at idle speed are other symptoms.
A clogged fuel filter blocks fuel flow to the engine, making the car difficult or impossible to start. Abnormal combustion and reduced power to the engine in turn leads to engine hesitation or problems when accelerating and also causes the vehicle to stall frequently. A clogged fuel filter also causes an engine to perform erratically, particularly at reduced speeds. Since air and fuel are unable to mix adequately, the engine's operation becomes rough at idle speed.