A fuel injector is an important component of a car engine. The key function of a fuel injector is to deliver fuel into the engine at the right time to ensure smooth combustion.

However, you might have never faced any problem with your car’s fuel injector especially if you timely use the best fuel injector cleaner.

But sometimes, over time, this component gets clogged, dirty, or even damaged and replacement is the only solution.

Let’s know more about a fuel injector: how they work? How will you know that the fuel injector has gone bad? How much does it cost for replacement and cleaning?

How Fuel Injector Works

The fuel injector controls the amount of fuel and ensures the right amount of fuel is delivered to the combustion chamber at the right time.

To better understand the working of the fuel injector, you will need to understand how the whole fuel system works.

When the fuel pump pushes gasoline through fuel lines into the fuel injectors and the ECU sensors get the message that fuel is needed, ECU activates the fuel injectors and then they open to allow the pressurized fuel to spray into the combustion chamber through their nozzles.

In the end, the fuel is compressed in the combustion chamber which then powers the car engine.

Signs & Symptoms of a Bad Fuel Injector

Most often, the fuel injector becomes faulty due to debris and clogging but it is not always as sometimes, the mechanical issues can also cause the breakdown of a fuel injector.

When the fuel injector goes bad it either spray the fuel in an inappropriate amount or sprays the fuel at the wrong time. However, in both cases, it affects the overall performance of the vehicle. In fact, the vehicle doesn’t run the way it supposed to be.

Let’s know about some of the important symptoms of a bad fuel injector that will help you get over the problem early.

1. Check Engine Light Turns On

When fuel injector doesn’t work properly, it either delivers less fuel or excess fuel. And when ECU gets the message through its sensors about the faulty fuel injector, it turns on the check engine light.

However, there could be so many reasons for illumination of check engine light so how you would be assured that the problem is with the fuel injector, for this, you can use an OBD scanner to read the problem code.

2. Engine Misfiring

A clogged or a faulty fuel injector prevents the engine from getting enough fuel that causes the engine to misfire when you drive.

In this situation, either your vehicle faces difficulty in acceleration or there is a delay when you step onto the gas pedestal.

If this problem is not resolved in time, it may cause other serious problems like engine overheating that result into some major problem. Therefore, it’s so important to keep your car’s fuel injectors clean.

3. Rough Idle

If you experience more rough idle noise, the bad injector could be the reason that is not delivering enough fuel to the engine. Because of the insufficient supply of fuel, the RPM of the vehicle goes down that causes rough and poor idling. If the RPM gets too low, your vehicle may stall and will require you to restart the vehicle.

However, there are other reasons also for rough idling such as a dirty air filter or a faulty spark plug but a bad fuel injector is the most common reason for rough idling.

4. Engine Stalling

Engine stalling is another symptom of a faulty fuel injector. When there is a blockage in the nozzle of the fuel injector or there is a fuel leak, the engine does get enough fuel for combustion that results into the ECU stops the engine.

5. Fuel Leak

If you notice gasoline around the fuel rail, fuel gauge or where the injector is connected to the fuel line, it means either the fuel injector has broken or cracked. And due to that, the gasoline has started leaking out which results into insufficient supply of fuel to the engine.

Generally, the fuel leak comes from the fuel injector seal that easily gets worn out over time.

6. Engine Surge

If the fuel injector gives out an excess spray of fuel to the combustion chamber, it may result into a sudden surge in the engine. It slows down the acceleration as well as decreases the RPM under constant load rather than remaining at a constant RPM.

This usually happens when there is some mechanical fault with the fuel injector instead of the damage or crack in the injector.

7. Bad Fuel Economy

A faulty fuel injector severely affects the fuel economy. As when the engine doesn’t receive enough fuel it requires for combustion, the ECU demands more supply of fuel to the combustion chamber.

However, the fuel reaches the fuel injector but is not received by the combustion chamber. Thus, very little fuel is received by the engine that results into bad fuel economy.

8. Engine Vibrates

When the fuel injector goes bad, the corresponding cylinder does not get the fuel it needs to be able to fire. And further, it results in the vibration into the engine when it completes each cycle without fuel.

Can You Drive With Bad Fuel Injector?

It is not that you can’t drive at all but driving a vehicle with a problematic fuel injector is completely unsafe for your vehicle as well as fuel economy.

If you overlook the signs of bad fuel injector for a longer period, it can cause serious issues with other components of your vehicle such as making the cylinder dead, pre-ignition of vehicle fuel, uneven heating, leaking fuel inside the engine compartment.

Therefore, you should get the bad fuel injector fixed on an immediate basis before this small repairable problem becomes highly destructive for your engine.

How Much Does a Fuel Injector Cost

Here, it is important to know that a faulty fuel injector doesn’t require replacement always. In most cases, the issues are resolved with professional cleaning. But if the fuel injector is broken or cracked, then replacement is a must.

No matter which makes and model you have, when it comes to the replacement of a fuel injector, it is always very expensive in every case.

Even it is about the replacement of a single fuel injector, the cost would come around between $250 and $350 where the labor cost would go around $120 to $160 and the parts would cost between $140 and $190.

However, we recommend replacing all the injectors at one time. It saves your money on labor costs. The labor cost for all the injectors would maximum go up to $500.

Can a Bad Fuel Injector Damage the engine?

A bad fuel injector can cause many issues to the different parts of the engine but it doesn’t damage the engine directly. The major issues it can cause are fuel leakage, slow acceleration, and injector solenoid failure.

However, technically there is no direct connection between a faulty fuel injector and the engine damage. But there are some issues caused by a faulty fuel injector that can make the engine stalled. If you go for timely repair and replacement, the engine would not get hurt in any way.


You would agree that most of us do not much worry about getting the problematic fuel injector repaired or replaced unless they become a serious problem for our vehicle. We become ready to experience uncomfortable hiccups, excess consumption of fuel, and delay in acceleration.

But I will suggest you not to ignore any sign of a bad fuel injector because it is possible you would be able to drive at initial stages but as the problem gets severe or worse, it will cost you much more than the amount you will pay for the repair at the initial stage.