If you feel that your fuel filter has a problem, remove the fuel filter and blow into it. If air doesn't pass through, then it is a sign of a clogged fuel filter. It signifies that the fuel filter needs to be replaced. Some of the other symptoms are mentioned below.
Trouble in starting the engine is the most common situation faced by car owners, if the fuel filter is clogged, as there is little or no supply of fuel to the engine. A problem with the fuel filter leads to starting issues. If the engine does not start at all, it is a sign that the fuel filter is totally clogged. If the engine takes too long to start, then it is a sign that the fuel filter is partially blocked.
You are at a signal, your vehicle stops and refuses to start. If you are navigating through steep slopes, the engine behaves as though you are running out of gas and eventually stops abruptly. If this is a regular feature with your vehicle, it means that the engine is not getting adequate supply of fuel. Insufficient fuel supply causes the engine to stall; fuel filter clogging can lead to insufficient fuel supply.
In some cases, the engine will start without a problem, however, it will stop, when it is supposed to be idle. It means that sufficient amount of fuel makes its way through the fuel filter, when the vehicle is running, however, when the vehicle is idling, the quantity of fuel is inadequate.
While driving at a low-speed, the car will experience sputtering problem. This is often the case, when the fuel filter has minimal blockage. However, over a period of time the fuel filter will have to be replaced or at least cleaned.
Problem in Accelerating
If in spite of stepping on the gas, the speed of the vehicle is the same (no acceleration), then it is a clear sign of clogging.
Engine Performance Issue
If you realize that your engine is no more fuel efficient and is also behaving erratically, it is time to clean or replace your fuel filter.
If the sound of your vehicle engine has changed and it is misfiring, a clogged fuel filter could be the reason behind the same. Very often it just needs a good clean up.
Exhaust Fume Odor
Sometime the car exhausts foul-smelling fumes. Such fumes indicate that the fuel filter needs replacement.
Carburetor and Injector Problems
When the fuel filter is clogged, sometimes, fuel will pass through the filter but will clog the carburetor and/or the injector, which will give rise to a number of other problems. This will cause the engine to stall leading to starting problems.
For the longevity of your fuel filter, it is always good to have it cleaned at regular intervals.
Whenever you notice any one of the above signs, clean it. The most simple method to clean the fuel filter is to remove the fuel filter and blow air through it. This proves to be of help in getting rid of small as well as big particles. Blow some more air through the filter. If air passes through the filter, it means that the fuel filter has been cleaned, if it does not, the filter needs to be changed.
Most of the vehicle manufacturers suggest that the fuel filters be changed once in five years or after the vehicle has run approximately 50,000 miles. But the mechanics choose to disagree with the manufacturers. They are of the opinion that changing a fuel filter once in five years is very unrealistic as the fuel filters tend to get clogged and need frequent / regular cleaning and / or replacement. To be more precise after every 10,000 miles.
Many times, the fuel may also contain alcohol or the fuel tank may rust, leading to a clogged fuel filter. Gasoline sold at 'cut-rate' gas stations contains a large amount of impurities, giving rise to fuel filter problems.