Header Image
Why trust BestReviews?
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We only make money if you purchase a product through our links, and all opinions about the products are our own. Read more  
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We only make money if you purchase a product through our links, and all opinions about the products are our own. Read more  
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We buy all products with our own funds, and we never accept free products from manufacturers.Read more 
Bottom line
Best of the Best
Redline Complete SI-1 Fuel System Cleaner, 15 oz.
Complete SI-1 Fuel System Cleaner, 15 oz.
Check Price
Expert Recommended
Bottom Line

Engine running rough? This product is rated to return your fuel injectors to nearly 100 percent efficiency in one treatment.


Red Line cleans fuel injectors, carburetors, valves, and combustion chambers with a blend of high-temp and low-temp detergents. It’s designed to reduce your engine’s need for octane by up to two points, which can save you money at the pump. Contains synthetic upper cylinder lubricant and is safe for continual use on neglected vehicles.


As with many fuel injector cleanser, some users reported no significant difference after using this product.

Best Bang for the Buck
Lucas 10003 Upper Cylinder Lubrication & Injector Cleaner, 32 oz.
10003 Upper Cylinder Lubrication & Injector Cleaner, 32 oz.
Check Price
Trusted Brand
Bottom Line

If you’re nervous about passing a smog test, use Lucas Oil to improve your engine’s efficiency.


A blend of oils, additives, and detergents bring deteriorated gasoline or diesel engines back to life. It also lubricates carburetors and injectors, resulting in fuel mixtures that burn cleaner for more horsepower. Designed to neutralize harmful effects of low-sulfur diesel and replace the need for leaded gasoline.


Improved power is nice, but this product could potentially increase fuel usage as a consequence.

Royal Purple 18000 Max Atomizer Fuel Injector Cleaner, 6 oz.
Royal Purple
18000 Max Atomizer Fuel Injector Cleaner, 6 oz.
Check Price
Bargain Pick
Bottom Line

A well-priced solution from one of the most reputable brands in the automotive industry.


Approved for both gasoline and diesel engines, this synthetic fuel injector cleaner stabilizes ethanol, maximizes horsepower, and improves responsiveness. Utilizes highly-concentrated polyether amine detergents to remove clogs and optimizes injector spray patterns. A great fit for those looking to improve idle smoothness.


Fuel economy gains may not be substantial enough to observe, depending on driving style.

BG 44K Fuel System Cleaner
44K Fuel System Cleaner
Check Price
Alcohol Free
Bottom Line

Cleans and remove deposits from your entire fuel system to prevent engine surges, stalling, hesitation, and power loss.


One 11-ounce can treats up to 20 gallons of fuel. Thoroughly cleans fuel injectors, intake valves, ports, and combustion chambers for an end-to-end rehabilitation. BG 44K is excellent at restoring old engines by removing carbon deposits, but it can improve performance of newer engines as well. Contains no alcohol and is compatible with all fuel system materials.


Comes in a can rather than a resealable or closable bottle, which can make storage messy.

Liqui Moly 2007 Jectron Gasoline Fuel Injection Cleaner, 300 ml
Liqui Moly
2007 Jectron Gasoline Fuel Injection Cleaner, 300 ml
Check Price
Simple Yet Solid
Bottom Line

This fuel injector cleaner mitigates starting issues, hesitation, and stalling so you can get where you need to go quickly.


Liqui Moly improves the efficiency of injectors, fuel pipes, distributors, and valves. The result is cleaner combustion, which leads to better idle quality, improved throttle response, and greater mileage. A fantastic option for engines with catalytic converters, this fuel injection cleaner helps your engine return to its factory performance.


If you drive a newer vehicle with low miles, you may not see any improvements at all.


We recommend these products based on an intensive research process that's designed to cut through the noise and find the top products in this space. Guided by experts, we spend hours looking into the factors that matter, to bring you these selections.

Category cover

Buying guide for best fuel injector cleaners

If your fuel injectors aren't functioning properly, your vehicle will use more gas, won't run smoothly, and might even stop altogether. The worst case scenario? Replacement fuel injectors for most vehicles cost upwards of $1,000. Fuel injector cleaners offer a simple and cost-effective solution to keeping your fuel injectors in top condition.

There are lots of brands to choose from, each touting a wide range of supposed benefits. To confuse the issue further, some people say fuel injector cleaners have little or no tangible effect.

Separating facts from hearsay is exactly what we at BestReviews do. It's our job to provide you with the information you need so you can be confident about your purchasing decisions. Our shopping guide below can help you find the right fuel injector cleaner for your needs.

Content Image
Experts say it's never too soon to keep your fuel system clean. Early treatment is like a vaccination for your vehicle – prevention rather than a cure.

What are fuel injectors?

Fuel injectors do the same job as carburetors, regulating the mix of fuel and air that enters the combustion chamber of your vehicle. Fuel injectors have become so popular because they do the job more accurately. For you, that means comparative savings on gas or diesel fuel and improved vehicle performance.

Why use a fuel injector cleaner?

Fuel injectors are finely tuned devices with narrow inlets and outlets. All fuel has some contaminants, which is why you have filters in your tank, fuel lines, and at the entrance to the injectors. These filters catch many of the microscopic particles, but a few still get through. The particles might be small, but they stick and accumulate. These particles from contaminated fuel can upset the high-pressure spray created by the fuel injectors.

That's not all. Gasoline and diesel both deposit a carbon residue. Tiny amounts, perhaps, but it builds up. This is seldom a problem in fuel lines, but over time the fuel injectors start to suffer and atomization is affected.

  • Too thin a fuel/air mix starves your engine.

  • Too rich a fuel/air mix makes your engine smoke.

Fuel injector problems can lead to the following:

  • Poor starting when engine cold

  • Misfiring engine

  • Shuddering and knocking engine

  • Smoking engine

  • Increased emissions

  • Poor throttle response

  • Increased fuel consumption

  • Lack of response under load

There's also a knock-on effect. A badly performing engine wears out more quickly. All of this has an impact on your transmission, too.

Content Image
Did you know?
Auto mechanics recommend regular fuel injector flushes and charge as much as $80 for the service. A bottle of fuel injector cleaner is a DIY solution at a fraction of the price, and you don't have to be without your car.

What do fuel injector cleaners do?

Fuel injector cleaners are designed to remedy the problems listed above. Your engine will run cleaner and last longer. The effects are most dramatic in older cars that are misfiring or idling badly, but all vehicles can benefit. Your mechanic will probably recommend a fuel injector flush when you get your vehicle serviced. The kind of fuel injector cleaners we're looking at here are a cheaper alternative that you can use yourself.

You add a fuel injector cleaner to your tank along with your gasoline or diesel. It is then pumped through the system during the normal use of your vehicle. There's no need to do anything special other than adding the correct amount to the tank when you fill up. In fact, fuel injector cleaners help clean the whole fuel system.

What’s in a fuel injector cleaner?

Exact chemical compositions vary, but basically these cleaners include a mixture of detergents for cleaning and oils for lubrication. While many of these products are noxious, there is increasing development of environmentally friendly products that use solvent-free detergents and synthetic oils.

Detergent: The two most common detergents are polyetheramine (PEA) and polyisobutylene (PIB). These detergents dissolve residues completely (if the residues were just broken down, larger particles from fuel pipes could move through the system and block the injectors). Once dissolved, the residues are injected through into the combustion chamber where they pass harmlessly through the exhaust. (Don't worry. They have no impact on catalytic converters.)

Lubricant: The lubricant also flows through the entire fuel system and into the combustion chambers. The oil applies a thin protective coating to any moving parts it touches, helping cool the system, prevent further buildup, and resist corrosion.

Content Image
Although some fuel injector cleaners claim to be environmentally friendly, most are flammable and/or toxic. Keep it out of reach of children and animals, and don’t store it where it could contaminate pet food or bedding.

Do fuel injector cleaners work?

Are some people disappointed with the results? Yes. A fuel injector cleaner isn’t a miracle performance enhancer. Many manufacturers claim their products will make your car run more smoothly, that performance will be improved, and fuel consumption will be reduced. What they're really saying is that those are the benefits you could see when compared with the way your vehicle is running with clogged injectors. Fuel injector cleaner can't make your vehicle run better than new, but the best fuel injector cleaners can make a tremendous difference to an engine that's running badly.

Choosing a fuel injector cleaner for your vehicle

While each manufacturer claims a variety of benefits for its products, almost all fuel injector cleaners do a similar job. These are the points you want to consider before buying:

  • Suitability for your vehicle: Not every product suits every car, truck, or motorcycle, so check. Many fuel injector cleaners work with gasoline and diesel, but not all of them do.

  • Frequency of application: For example, do you want to be adding something every time you fill up or just when you change the oil?

  • Cost: The fuel injector cleaners that are used less frequently are often more expensive.

  • Brand: Cheap, no-name products may not live up to the claims. Recognized brands have a reputation to protect and are likely to have spent significantly more on research and development to create a more effective product.

  • User feedback: People are much more likely to complain than compliment. If dozens or hundreds of actual users praise a particular fuel injector cleaner, it must be doing some right.

Fuel injector cleaner prices

Comparing fuel injector cleaner prices isn’t easy. Containers are different sizes. Dosage amounts and time periods differ.

Cheaper fuel injector cleaners are often intended for regular use. One pack we looked at costing $15 treats 100 gallons of fuel. Another costing $14 should be used every 3,000 miles.

Other additives costing $20 to $25 per bottle treat just 20 gallons of fuel, but the description is a little misleading. It's only intended to be used with a single tank of gas every 10,000 miles or so. If you have a compact car with a small fuel tank (or a motorcycle) you probably won't need the whole bottle.


Too low a fuel level can affect your fuel pump. The fuel pump is located in the bottom of your tank. If you let the level drop too low, the pump gets hot. It's not enough to cause any danger, but it will reduce its efficiency and working life. Keep your fuel tank a quarter full or above to prevent this.

Too low a fuel level can contaminate your fuel tank filter. No fuel is 100% clean, and dirt particles collect in the bottom of the fuel tank. If the tank gets too low, you risk sucking these particles into your fuel tank filter and blocking it.

Add fuel injector cleaner to a half-empty tank. Although it's never recommended to let your fuel level get very low, if you're adding a fuel injector cleaner to the tank, you should do it when it's around half empty and then fill with fuel to get the most effective dilution.

Know the signs of fuel injector problems. Trouble starting, a rough idle, and difficulty when accelerating or under stress (like when towing) are all symptoms of fuel injector problems. These can also be related to faults in the fuel pump or fuel filter. Using fuel injector cleaner can be a quick, cheap, and effective way to resolve one of those problems before you need to look further.

Content Image
Fuel injector cleaners work with all kinds of systems, including those in motorcycles, agricultural vehicles, and marine engines.


Q. How often do I need to use fuel injector cleaner?

A. If you search online for answers to this question, you'll find that everyone has an opinion! Some say every time you fill with gas, some say with every other tank, once a month, once every X thousand miles, and so on. Unless you receive qualified professional advice to the contrary, we recommend following the manufacturer's advice – it knows best what the product can do. Many fuel injector cleaners are intended to treat a given amount of fuel (100 gallons, for example). However, the internal combustion engine is a complex mechanism, and no two are quite the same. If you're dissatisfied with the results you're getting, try a different brand next time.

Q. Can I use fuel injector cleaner in turbocharged or supercharged engines?

A. No problem at all, as long as you're running regular gas or diesel you buy at the pump. As far as we’ve been able to establish, these products haven’t been tested with racing fuels like nitromethane. If you're running any kind of race car, a fuel injector cleaner could have a damaging rather than beneficial effect.

Q. Some people say fuel injection cleaners don't make any difference. Is that true?

A. It’s possible that a particular product didn't make a noticeable difference to an individual vehicle, or that the driver didn't notice a marked improvement. But that doesn't mean the product doesn't work or that you should neglect something that will prolong the life of your vehicle. On a well-maintained, low-mileage engine, the effects will naturally be less dramatic than on an older model with 200,000 miles. Mechanics recommend flushing your injectors from time to time. The overwhelming majority of users we researched reported positive results. It does no harm and can be of tremendous benefit, so what’s the downside?

Our Top Picks