PTC PP3940 Fuel Filter Traps fuel contaminants before they enter the engine's fuel delivery system Symptoms of clogged fuel filters, rough running, poor acceleration, decreased fuel economy Removing gas cap before replacing the fuel filter will release system pressure; replace cap after filter installation Fuel filters are a last stop effort to feed clean gas to the engine Fuel filtration system prevents foreign material from entering the engine while allowing enough fluid or air flow to keep the engine running properly