Bad Fuel Filter Symptoms, Causes, and Other Important FAQ

In order to function properly, the engine needs a sufficient supply of clean fuel. A fuel filter helps achieve this by trapping dirt and other contaminants before they can enter the engine. Over time, however, it’ll collect too much dirt and interfere with the flow of fuel. You’ll need to replace it before it starts causing problems for your vehicle.

What Are the Symptoms of a Dirty Fuel Filter?

To help you determine if your fuel filter needs replacing, here are common signs to look out for:

Sluggish Acceleration

You may feel normal acceleration until you begin to apply a lot of throttle passing a car or driving up a hill. If you feel the power fading awaylike you’re releasing the accelerator when you’re not, the fuel filter is the first place to look.

Power Loss

This is likely to happen while you’re driving up an incline or passing a vehicle.

Fuel Pump Noise

As its name suggests, the fuel pump pumps gas from the fuel tank to the injector or carburetor. A dirty fuel filter forces it to work harder to supply enough gas to the engine, and all that extra strain causes the pump to make noise. If this goes on for too long, the added stress can also cause the fuel pump to fail.

Illuminated Check Engine Light

A dirty fuel filter is also likely to trigger the check engine light on your dashboard. Low fuel pressure, an increase in emissions, and other similar issues are all red flags to your PCM. As soon as it detects any of these issues, it’ll turn on the check engine light to warn you.

Is Difficulty Starting the Car a Symptom of a Dirty Fuel Filter?

The only case in which this might happen would be if you pumped your tank full of fuel that was totally saturated with rust or a similarly suspended contaminant that can make it through the pump to the filter. If that’s the case, the fuel filter isn’t the cause, it’s an effect of a bigger problem that needs to be dealt with.

The only case in which a dirty fuel filter can cause difficulty starting a car would be if you pumped your tank full of fuel that was totally saturated with rust or a similarly suspended contaminant that can make it through the pump to the filter. If that’s the case, the fuel filter isn’t the cause, it’s an effect of a bigger problem that needs to be dealt with.

– Richard McCuistian, ASE Certified Master Automobile Technician

Similarly, a dirty fuel filter is usually not the cause for rough idling, but extremely low fuel pressure can also cause your engine to lurch or misfire.

What Is a Fuel Filter For?

A fuel filter is specifically designed to prevent natural impurities, debris, and other contaminants found in gas from entering the fuel system. All that dirt can damage components such as the fuel injectors and cause the entire fuel system to fail.

What Causes a Clogged Fuel Filter?

As the fuel filter does its job, it’ll naturally collect many contaminants over time. This is why most manufacturers recommend replacing the fuel filter every 20,000 to 150,000 miles. Unfortunately, some people might forget to replace their fuel filter, causing the particles to clog the filter and prevent it from doing its job.

How To Check Your Fuel Filter

The best way to check your fuel filter is to ask a mechanic for help. However, if you’re confident in your skills, consider these helpful tips on how to tell if your fuel filter is bad:

• Drain as much gas as possible out of the fuel filter.
• Thoroughly clean the inlet to the fuel filter with a towel.
• Lay another towel on your workbench before gently blowing into the inlet for an easier cleanup.
• Allow the towels to dry outside or in a well-ventilated area before throwing them away.

If you blow into the inlet and find that no air is passing through, then the filter is likely clogged and needs replacing.

Pro Tips are nuggets of information direct from ASE-certified automobile technicians working with CarParts.com, which may include unique, personal insights based on their years of experience working in the automotive industry. These can help you make more informed decisions about your car.

Pro Tip: Blow backward through the filter into a container and see what’s clogging it. If you see rust or water, you might consider having the tank cleaned.

How Much Does a Fuel Filter Change Cost?

The exact cost will vary depending on several factors, such as your vehicle’s year, make, and model. However, the average cost of replacing a fuel filter ranges from $90 to $142, including labor. If you plan to replace it yourself, you can expect to spend anywhere between $10 and $920.

Other Filters in Your Car That You Should Inspect

When you bring your car in for its regular maintenance, your mechanic will also check if other filters need replacing. Here are other filters you should also inspect:

Engine Air Filter

As its name suggests, the engine air filter captures dust and other contaminants in the air that could damage the engine.

Transmission Filter

Automatic transmissions come with a filter that keeps dirt and other debris from entering and harming the hydraulic system.

Cabin Air Filter

This allows you and your passengers to breathe clean air by filtering dust, pollen, and other particles from the air before they can enter the cabin through the vents.