What is the Best Fuel Injector Cleaner in 2024?

If you are in a hurry and just want to find out what the best fuel injector cleaner is, then we recommend Lucas Complete Fuel Treatment as the best one.

Have you noticed a decline in the fuel efficiency of your vehicle? Does the engine seem a bit slower when responding to an acceleration? Maybe you hear a knocking sound when driving?

If you responded yes to any of these questions, you may have a case of clogged fuel injectors. Fortunately, solving the issue may be as simple as pouring the right additive in your fuel tank. Read our fuel injector review to find the best fuel system cleaner to restore your engine to mint condition.

Here are the best fuel injector cleaners we’ll be reviewing:

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All of our reviews are based on extensive market research, expert input, and practical experience. We invest time and resources to analyze the products. This way, we can offer you genuine, accurate guides to help you get the best pick for your needs.

What are Fuel Injectors anyway?

Fuel injectors, as the name suggests, are the engine parts that inject, that is spray, fuel in the motor. They are nozzles that squirt gas into the engine. Easy enough.

As with all internal combustion engines (ICEs), the fuel has to be mixed with air to create fire and thus power. But a precise combination of air and fuel is necessary.

When you step on the gas pedal (or turn your bike handle) you let air into the engine. A computer module, the Engine Control Unit (ECU), senses the increase in airflow. It then increases the flow of fuel through the injectors to create the right mix and generate more power. So far so good.

Why do I Need a Fuel Injector Cleaner?

Fuel, whether gasoline or diesel, has a lot of stuff in it. When it burns, the liquid part evaporates and leaves behind solid residues that resemble varnish or gum. These residues build up over time and can eventually clog up passageways of the engine system.

In fuel-injected engines (i.e., practically all modern engines) the nozzles are usually the first to suffer from build-ups. As they get clogged up, their spray is not optimal, the air-fuel ratio necessary to generate power gets out of whack, and you’re left with a sluggish and less efficient motor.

The usual symptoms are decreased fuel efficiency, that is less miles per gallon (MPG), and a slower response to acceleration. A knocking sound in the motor could also be present while driving (due to fuel buildups in the combustion chamber).

And in case you’re wondering, the old trusty carbureted engines weren’t free from these kinds of problems either. They burned fuel as well, thus suffered from the same buildups, just in different areas.

Fuel injector cleaners, and more in general fuel system cleaners, are fuel additives that help you clean the fuel system. They are basically fluids that you pour into the gas tank and that dissolve the buildups.

Using a good fuel injector cleaner can solve the buildups, thus restoring your engine to its original condition. This in turn restores fuel economy (MPG) and responsiveness upon acceleration.

A close-up of an engine block

Let me stress that, though: fuel injector cleaners restore your engine to its original condition. If you have a clogged engine, then they give you “better performance and improved fuel economy”. That’s why they write that on the label. If your engine is already fine, they cannot magically further improve its quality. So don’t expect that. Don’t expect significant improvements if your engine is already working fine and you haven’t noticed a loss of efficiency in the first place.

However, using a fuel system cleaner regularly prevents clogs from forming in the first place and keeps your fuel system in tiptop shape. Since replacing damaged injectors is very expensive, you might consider this a good investment in prevention.

How to Choose the Best Fuel Injector Cleaner

Now, here’s the fun part. We could be talking about the various chemical compositions and their cleansing power. However, knowing a bunch of solvent acronyms and their efficiency is not going to help you very much. And you know why? Because most of the cleaners don’t disclose their composition. You wouldn’t either if that was the only thing differentiating your product from the competition. It’s a trade secret!

What’s a guy to do then? Get some good recommendations and know thyself.

For the first part, we’ve got you covered. For the second part, however, you’ll have to scour deep into your soul. Read on.

Though we can’t categorize them on their formula, we can split the cleaners according to their suggested frequency of use:

  • frequent use, usually every time you fill the fuel tank (i.e., every fill-up)
  • occasional use, usually every oil change, or every some thousand miles

If the cleaner instructions say that the product should be added with every fill-up, the detergent will generally be weaker, or shall I say gentler, than products whose suggested application is less frequent.

Don’t jump to the obvious conclusion though. There’s a reason if the maker of that cleaner actually suggests you not to use it too much. Using too much of a stronger product can cause damage to the fuel system by ruining sensors and other engine controls. Plus stronger doesn’t necessarily mean more efficient since we’re talking about complex formulas. It just means more aggressive.

One of our favorite products, the Lucas Complete Fuel Treatment, actually belongs to the “every fill-up”/gentler category. But it is in our experience one of the most effective at removing injector buildups.

It ultimately comes down to your maintenance habits and your dedication. Thus, know thyself.

A vintage car dashboard

If you are used to performing regular maintenance on your vehicle, and you are dedicated to it, then go for a frequent-use cleaner. Frequent-use products keep your engine in consistently optimal shape and operating at its best.

If, on the other hand, you are not that committed, then you’re probably better off selecting a product from the occasional-use category. These will give you more slack, and give the engine that occasional cleanup to restore its condition.

How to Use a Fuel Injector Cleaner

Alright, this part is very easy. As we said, fuel injector cleaner is a fuel additive. That means you just add it to your fuel.

And that explains why most of these products come in a bottle with a longer neck: so you can stick it into the gas tank opening and pour it in. If the neck is not adequately long, be sure to use a funnel to avoid making a mess.

Always follow the specific instructions on the label of the product you selected. In particular, use the indicated amount at the indicated frequency. It’s important not to overdo it, especially with the occasional-use cleaners. Best case scenario, you’re just wasting it. Worst case, you could damage your fuel system.

As far as when to use it, follow the instructions if present. If no particular timing instruction is present, then it’s usually preferable to add the cleaner before adding more gas. The splashing of the fuel on top of the cleaner gives a better blending. Plus, you don’t run the risk of overfilling the tank, as the gas pump will stop supplying once it’s full.

These are the Best Fuel Injector Cleaners

Frequent-Use Cleaners

These cleaners are meant to be used more frequently, usually at every fill-up.

They improve fuel quality (useful if you sometimes use low-quality fuel) and keep your fuel system consistently clean and lubricated. Select one of these if you are dedicated to your car maintenance.

Best Overall: Lucas Complete Fuel Treatment

This is in our opinion and according to our extensive research the best fuel additive on the market today. Its cleaning power is outstanding and we’ve witnessed it bringing back to life some of the most desperate clogged injectors.


  • Extremely efficient in removing fuel injector buildups
  • Cleans and lubricates the fuel system and engine
  • Works both on gas and diesel engines
  • Can be used both on fuel injected and carbureted engines
  • Stabilizes the fuel so that it doesn’t go bad after a couple of weeks (if you don’t use it)
  • Improves octane rating (i.e., the quality) of gas
  • Overdosing is not harmful


  • Avoid contact with skin as it can cause irritation
  • Avoid spills on the car’s body as it can stain (use a funnel, especially with the larger container)
  • Contains some chemicals considered harmful for the environment

Because of its extreme efficiency and its wide compatibility, Lucas Complete Fuel Treatment also deserves the best diesel injector cleaner award in our frequent-use product review!

Also Great: Royal Purple Max Atomizer Fuel Injector Cleaner

Royal Purple is a Texas-based company very well known and esteemed by vehicle enthusiasts. And their fuel injector cleaner is one of the best gas additives and an excellent product you can absolutely rely on.


  • High-performance fuel injector cleaner, specially formulated to solve problems with fuel injection engines
  • Suitable for both gasoline and diesel engines
  • Stabilizes the fuel so that it doesn’t go bad after a couple of weeks of not being used
  • Though based on PEA, one of the strongest cleaning agents available in fuel additives, it does not harm vehicle emissions equipment


  • Requires a funnel to pour it as the container doesn’t have a long neck
  • Tends to be more expensive per gallon of treated fuel

Occasional-Use Cleaners

These cleaners are meant to be applied more sparingly, usually at every oil change, or every year, or every couple thousand miles. They give your engine a cleanup and restore its condition.

With these products it is very important not to overdo it, as they are generally based on more aggressive detergents that could damage your engine when applied incorrectly. Always follow the guidelines on the product label. It’s actually better to err on the side of laziness and apply them less frequently rather than overusing them.

Select one of these if you want a more relaxed kind of routine, or you’re just not that committed to your vehicle maintenance.

Best for Infrequent Use: Red Line Complete Fuel System Cleaner

Red Line is a name particularly famous in the racing industry. The California-based company has since 1979 become synonymous with motorsports and racing-grade high-quality products. And their Red Line Fuel System Cleaner is one of the top-sellers of all time.

Red Line’s patented formula gives most users 100% efficiency after the first use. Its recommended use of every 3000 miles grants it the best for infrequent use spot in our review. Hands-down.


  • Cleans and lubricates all petrol-based engines
  • In most cases nearly 100% efficient after the first treatment
  • Indicated for both fuel injected and carbureted engines
  • Enhances fuel stability
  • Improves the fuel quality, reducing gum and varnish formation
  • Long neck for easy pouring


  • Only suitable for gasoline engines (not suitable for diesel engines)
  • Comes in a small size that may not be enough alone to treat a larger engine system

Best for Infrequent Use on Diesel Engines: Sea Foam Motor Treatment

Trusted by mechanics since 1942, Sea Foam was born with a focus on safe and effective products that help keep all types of gas and diesel engines running their best.

Their Sea Foam Motor Treatment is an all-around great product. It’s triple action, ultra-wide applicability, and through-the-roof customer feedback rightfully earn it a spot in our review.


  • High-performance fuel injector and carburetor cleaner
  • Cleans and lubricates the entire fuel system
  • Suitable for both gasoline and diesel engines
  • Can additionally be used as an oil additive to dissolve harmful residues and deposits
  • Can be used as a stabilizer for gas or diesel fuel so that it doesn’t go bad for up to 2 years


  • Requires a funnel to pour it as the container doesn’t have a long neck

Because of its triple action and its ultra-wide applicability, Sea Foam Motor Treatment also deserves the best diesel injector cleaner award in our occasional-use product review!


There’s a lot of confusion when talking about fuel system/injector cleaners. But when you boil it down, it’s just a matter of cleaning the engine passageways so that it can run properly. These are not magic concoctions. They restore the engine to a cleaner condition and keep it running cleanly if applied regularly. But you should not expect to see performance improvements if you have not seen a loss of performance in the first place.

As far as what kind to choose, it ultimately comes down to your maintenance commitment.

For the frequent-use category, we consider the Lucas Complete Fuel Treatment the overall winner. It’s perfect for both gasoline and diesel engines, fuel-injected or carbureted. Its cleaning properties have few equals, and it also improves fuel quality and stability. As its name suggests, it is a complete fuel treatment: just pour it in at every fill-up and you can rest assured that your engine will consistently run in tiptop shape.

For the occasional-use category, we love the Red Line Complete Fuel System Cleaner. It works wonders for all gasoline engines, fuel-injected or carbureted. It cleans and lubricates the fuel system and is nearly 100% efficient after the first treatment. It enhances fuel stability and improves fuel quality, reducing gum and varnish formation in the first place. With its long recommended application frequency of every 3000 miles, it’s the perfect occasional-use cleaner to add to your vehicle maintenance toolset.

Finally, in addition to a good fuel system cleaner, for the maintenance of an aging vehicle we absolutely recommend employing a great high mileage oil. Combined with the use of a cleaner, regular oil maintenance with a high mileage oil will counter the side-effects of an aging engine, ensuring that your vehicle keeps running at peak performance for many more years to come.

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