The fuel filter acts as a permeation barrier that removes impurities, deposits, contaminants and rust from the fuel before it enters the fuel injection system and ultimately the vehicle engine. The fuel filter may be a filter cartridge with a filter material composed of paper inside. Most technicians will replace the fuel filter during the normally scheduled maintenance interval.

But for the sake of argument, let's say your car hasn't been serviced in a while. How do you know it's time for a new one?

Here are some key things to note:

  • Your vehicle is difficult to start. This may be the result of a clogged filter. It might start eventually, but if it takes a while, that's a sign that fuel can't get through the filter into the engine.
  • Your car, truck or SUV may not start at all. But you probably can't blame it all on the fuel filter. There may be other causes, including a fuel pump failure.
  • Excessive vibration at idle. Most vehicles have slight vibrations, but if you're waiting for a traffic light to change, or if you find yourself in stop-and-go rush hour traffic and feel your SUV shake or idling roughly, this could indicate a clogged fuel line, Most likely the fuel filter.
  • Rough, slow cruising. Steady highway cruising, followed by low-speed driving, is usually a sign of a clogged fuel filter, experts say. Highway speeds require higher fuel flow, which may mask the problem. Slower speeds are used less. But a clogged filter will show up at this lower speed.
  • The car turns off while driving. Ignoring the symptoms listed above can cause your vehicle to stall, especially when you need it most. Such negligence may result in injury to your vehicle and yourself.