If One Fuel Injector Is Bad Should I Replace Them All?

Have you a strong smell of gasoline while driving? or maybe your fuel efficiency significantly dropped?

These could be signs of a leaking fuel injector.

In our previous article, we discussed the common causes and symptoms of a leaking fuel injector. If one of your fuel injectors had come to a point where it couldn’t be cleaned or fixed, then you have to replace it.

But the question now is should you replace all fuel injector when one of them went bad? In this article, let’s find out if it’s worth replacing just one fuel injector or replaces the whole set.

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How Does Fuel Injector Works?

Fuel injectors are responsible for delivering fuel to the engine. They use high pressure to spray a fine mist of fuel into the engine’s cylinders, which is then ignited by the spark plugs to power the vehicle. Understanding how fuel injectors work can help you identify potential issues and make informed decisions about maintenance.

If One Fuel Injector Is Bad Should I Replace Them All?

In most cases, all fuel injectors are replaced together to ensure uniform performance and prevent future issues. If you choose to replace only one fuel injector, it lead to uneven fuel distribution and potentially cause damage to other parts of the engine. Although, you may choose to just buy and replace one fuel injector depending on several factors such as:

  1. Mileage and age of the car
  2. Budget
  3. Cause of fuel injector failure
  4. Your skill should you choose to DIY

In our experience, we have seen many cases where replacing just one faulty fuel injector doesn’t solve the problem. The reality is that fuel injectors don’t wear out evenly and typically don’t fail simultaneously.

I recall a case where a customer brought in their car with a faulty fuel injector. After replacing the bad one, the car ran well for a few weeks. However, the customer reported more problems soon after, and another injector failed. This continued happening until all fuel injectors were eventually replaced.

It’s always best to replace all fuel injectors at once to ensure optimal performance and avoid potential future issues. Plus, doing it all at once saves on labor costs since you don’t have to keep taking the car in for multiple repairs.

It’s a proactive approach that ensures the longevity of your vehicle and saves you time and money in the long run.

Nevertheless, make sure to consider all factors before making a decision. Here are the things that you should think about:

1. Mileage and age of the car

Of course if the vehicle is new, it may only need a minor repair to replace one injector. When we say “new” it means the car is a few years old and the mileage is 50,000 miles and below.

However, the cost of replacing one fuel injector can be expensive and not all manufacturers make it easy to replace an injector.

If the car’s engine is over 10 years old or has over 100,000 miles on it, a single injector failing could mean that the others are old and on the verge of failing as well.

Rarely will more than one injector fail at the same time. A good diagnostic mechanic should check the whole system because other parts could be the cause (plugged fuel delivery lines or broken wires in the injector harness etc.)

2. Budget

You can expect to pay between $350 and $850 on average for one set of fuel injectors. A range of factors affects the cost to replace a fuel injector. Smaller vehicles with fewer cylinders will require less expensive parts and come in at the lower end of this spectrum.

Larger, high-performance engines command higher prices for replacement parts and labor because these cars typically need more time on shop racks when getting fixed up as well due to their complexity levels.

If you’re low on funds and still have time to spare, it’s unwise to spend more money unless you know for sure that you need to. But if a couple of hundred dollars won’t bother you much, it’s worth the investment.

Cost of Replacing Fuel Injectors: Make and Model

One of the key factors to consider when it comes to fuel injector replacement is budget. The cost of replacing fuel injectors can vary greatly depending on the make and model of your vehicle. This table showcases the average cost of fuel injector replacement for some of the top 10 popular car models.

Make and ModelAverage Replacement Cost
for Fuel Injector Set
Toyota Camry$800-$1,200
Honda Civic$600-$1,000
Ford Focus$700-$1,200
Chevrolet Silverado$900-$1,500
Ram 1500$1,000-$1,800
Toyota RAV4$800-$1,200
Nissan Rogue$700-$1,200
Honda CR-V$600-$1,000
Ford Escape$700-$1,200
Chevrolet Equinox$800-$1,200
Average cost of fuel injector replacement*

*Note: Prices are only estimates and were accurate as of February 2023. The total replacement costs may have changed since, our figures should be used as a starting point for your own research.

3. Cause of Fuel Injector Failure

Injectors typically last a long time and only fail when there is an underlying cause. These are rare, but the longer you keep your vehicle running, the more likely it is that you will have to deal with one.

Here are some of the most common causes of fuel injector failure

  1. Dirty Fuel: Dirty fuel can clog the injectors and reduce their performance. This can cause misfires, decreased fuel efficiency, and a loss of power.
  2. Wear and Tear: Over time, the mechanical components of the fuel injectors can wear out, leading to leaks and reduced performance.
  3. Electrical Issues: Fuel injectors are controlled by the engine’s computer, and problems with the electrical system can cause them to fail.
  4. Fuel Pressure Issues: The fuel pressure must be within a specific range for the injectors to function correctly. If the pressure is too low or too high, it can cause damage to the injectors.
  5. Fuel Contamination: Contaminants in the fuel system, such as rust or debris, can cause the injectors to fail.

One way to make sure there are no underlying issues is a thorough diagnosis of the fuel injection system. You have to make sure that there are no problems with the fuel pressure regulator, wiring harness, or injector driver module before you replace the failed injector.

It is important to do this because there could be an underlying cause that may come back to bite you later.

4. Your skill should you choose to DIY

According to YourMechanicfuel injector replacement needs specialized cleaning and test equipment.

replacing fuel injector

If you are not confident that you have the knowledge and tools to do it, you should find someone who does. We’ve seen people who don’t have the necessary skills or discipline replace parts they don’t need, which then cause issues because of their improper installation.

It would be a pain to have everything taken apart and then put back together, only for the problem to still exist or even get worse. Now you get to try and see if it was something that you messed up or misplaced, or if the part you replaced was bad.

How to tell if a fuel injector is bad?

There are many things to look for to determine if your fuel injector is bad. Some of the symptoms are the following:

  1. The check engine light is on
  2. The car idles rough
  3. You can smell gas
  4. Engine misfire

It is important to diagnose the problem before you replace your fuel injectors. Knowing what is causing the problem will help narrow down the possible cause.

If one of these signs is present, then it is a good idea to have a certified mechanic check out your vehicle. And inspect all components that could be causing the trouble. They can pinpoint the exact source of the issue and will be able to replace the part that is causing the problem.

You can use an OBDII scanner to get a code for the injector to narrow things down. If the code is for a specific injector, then that is the issue.


A single bad injector can cause a whole system’s worth of problems. When it does fail in older cars, the others are likely to follow suit soon after. Unless you need to fix other things that may be causing your fuel injector to fail (which is usually the case), replacing only one will do little good and cost time and money.

If the car is old and you have the budget, replacing all of them can help you avoid future problems. You just have to find the source of your troubles and act on that or else it will cost you more in the long run.

If you are low on cash, it is best to wait for a little before going ahead with replacement because changing nothing now may mean not having to make another big repair later.

It is a good idea to run a diagnostic scan and see if there is anything else that might be causing the issue before replacing your injector. If you have a code for your bad injector, it’s best to replace only that one instead of the whole system. You may need to do more troubleshooting after this initial fix if the issue does not go away.

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