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10 Symptoms Of Faulty Fuel Injectors?

When it comes to vehicle maintenance, there are some things you can do on your own and others that require the help of a mechanic.

Replacing faulty fuel injectors is one of those tasks best left to an experienced automotive professional. It is an essential component of a car, and not maintaining them regularly may result in sudden breakdowns, but today, we will be sharing with you some of the common symptoms of a faulty fuel injector.

This helps you to determine the problem when your car stops working all of a sudden in the middle of the road. Here’s what you need to know about testing whether or not your car has faulty fuel injectors.

What are fuel injectors?

Before we discuss the symptoms, it is essential to know what this car component does to understand it better.

A fuel injector cleans the car’s engine by forcing fuel into it at high pressure and then spraying it onto its cylinder walls. It also uniformly mixes the gasoline with air so that combustion is more efficient once an ignition – say from a spark plug – happens.

Fuel injectors are valves with a needle-like nozzle and plunger. A pump pressurizes fuel and sends it through the injector. When the plunger moves – driven by the engine – it opens up a passage that is covered by a needle-like nozzle.

In some types, this controls fuel as it goes into an engine. In others, it meters out precise amounts of fuel for more efficient combustion.

10 Symptoms of Faulty fuel injectors in a car

1. Engine warning light

The first thing you need to do is check your engine warning light. This will be the easiest way to determine if a faulty fuel injector has brought on a sudden breakdown. If it stays on for more than 3 minutes, there is no problem with the car’s computer but a serious problem with one or two of its parts.

2. General Performance of the car

If you have been having problems with your car lately, for example, noticing that it is taking longer to reach the speed you desire or that it has been stalling on a regular basis then chances are one or two of its components, including fuel injectors may be faulty. If there are no warning lights, but you have been experiencing these problems, then there may be a problem with your fuel injectors.

3. Engine turns on but does not start

When checking for faults in the car’s fuel system, one of the most common causes is a faulty spark plug or faulty ignition coil. This happens when the engine turns over, but it does not start. What you should do is to replace spark plugs and ignition coils with new ones and if the problem still persists, then chances are that there may be a faulty fuel injector or two.

4. Engine idles rough

A car’s engine performs poorly when its components are faulty. One of those components includes a faulty fuel injector. In this case, if your engine idles rough with the engine warning light out, it may indicate faulty fuel injectors.

5. Poor Performance

Another common symptom of faulty fuel injectors is hesitation when you try to accelerate your car’s performance. When attempting to accelerate your car and there is a delay in the engine’s response, in most cases caused by a faulty fuel injector.

6. Poor Fuel Economy and Engine Performance

If your car suddenly starts consuming more fuel than usual and does not bring on the type of performance you expect it to when accelerating, then there is definitely something wrong with the fuel injector. 

The car’s engine should get the right amount of fuel, and if this doesn’t happen, you can experience serious issues with the car’s engine. 

7. Engine won’t start after being switched off

Another most common cause of stopping your car’s engine from starting, especially when it has been switched off for a minute or so is because its components are not working properly. For this reason, you need to check that all the electrical components are working before diagnosing fuel injectors.

8. Bad fuel smell

One of the most common causes of a bad fuel smell in your car is because it has been burning more oil and old fuel than usual. As far as mileage goes, this means that your car’s components may not be working properly, including its fuel injectors.

9. Excessive Black Smoke from Exhaust

If you notice that your car is emitting excessive black smoke from its exhaust, then there may be a problem with the car’s fuel injector, and you should get it fixed as soon as possible.

10. Engine vibration and misfire

If you notice that your engine shakes and vibrates when it starts up as well as while driving, especially at idle speed, then most likely there is a problem with fuel injectors.

A faulty fuel injector can cause an engine to run roughly and produce carbon monoxide and other harmful gases that pollute the atmosphere. If you notice any of the above symptoms, then it is advisable that you take your car to a mechanic for diagnosis as soon as possible.

How to maintain fuel injectors?

Fuel injectors should be maintained as recommended in the owner’s manual. If your car needs cleaning, you can take it to a mechanic, or do it yourself if you feel comfortable enough.

Make sure to follow instructions and wear protective gear (goggles and gloves). Remember that fuel is highly flammable: don’t smoke while doing this and keep a suitable fire extinguisher nearby.

One thing that can help keep it clean is to use a fuel injector cleaner, which you can purchase at most auto stores, but make sure the product is compatible with your vehicle’s manufacturer guidelines before using anything not sold specifically for your make and model.

Fuel injectors can become clogged with carbon deposits over time, which can cause the car to idle roughly or fail to start. If this is happening, you might be able to clean them with special tools after disconnecting the electrical connection, but if it continues to happen for a long period of time (and with increasing severity) you might need to have your fuel injectors replaced entirely.


Symptoms of faulty fuel injectors can be very hard to pinpoint, and if the car is running smoothly, you might not notice anything wrong. If your vehicle suddenly starts having problems when it never did before or had been showing signs of poor performance with no explanation, then a problem with the fuel injector could be the cause.

Of course, it’s also possible that the problem is something else entirely and there is absolutely nothing wrong with your vehicle. Still, if you’ve noticed one or more of the symptoms listed here and don’t know what’s causing them, it’s probably a good idea to have your car checked out by a professional just in case.

And yes, this should go without saying, but if you’re having serious problems with your car it’s important not to drive it. Many of these symptoms could indicate a much more serious problem that needs immediate attention. The last thing you want to do is make a small problem into a big one.

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