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Fuel System Cleaners: Worth it, or Snake Oil?

If you go into your local parts store, you’ll see dozens of fuel system cleaners to choose from. So, which one should you buy, and do you even need them at all? The gas companies tell us that there are detergents right in the gasoline that keep your car running like new. So why does your car feel like it’s losing power and the fuel mileage drops after a few thousand miles of driving?

Carbon buildup in the fuel intake area

Even the top brands of gasoline cause corrosion from ethanol and water and leave carbon deposits in your fuel system, specifically your fuel injectors and on the back of the intake valves. This can result in combustion problems due to improper fuel mixtures entering the combustion chamber.

Carbon buildup in the fuel intake area needs to be cleaned in order to keep your car running at peak efficiency. So fuel system cleaners are an important part of regular maintenance on new-generation engines.

Other fuel system parts that are affected by these deposits are intake ports, tops of the pistons and cylinder heads. Deposits form on these vital parts and cause a variety of issues such as hesitation, stalling, knocking, pinging and loss of acceleration and reduced fuel economy. But the main parts that are the most susceptible to deposits are the fuel injectors and intake valves.

Deposits affect power and fuel economy

Fuel Intake Diagram

Fuel injectors have very fine tolerances in the pintles which allow the fuel to disperse from the injector. They deliver an atomized spray of fuel that when mixed with the proper air mixture, detonates in the combustion chamber. These fine tolerances in the pintles get dirty over time and the spray pattern becomes irregular and the spray turns into droplets that are harder to combust. This effects power and fuel economy.

The intake valves and ports are also very susceptible to deposits and the carbon buildup acts like a sponge and reduces the amount of fuel that enters the combustion chamber. The carbon builds up on the back of the intake valves from un-burnt fuel and the extreme heat. This also prevents the proper fuel mixture from entering the combustion chamber resulting in an overall decrease in performance.

Use a fuel system cleaner on a regular basis

Keeping fuel injectors and intake valves free of deposits is critical to optimal performance. To restore these components to their original specs, they need to be cleaned. This is why fuel additives are important to use on a regular basis. Fuel additives contain detergents that can clean these fuel system parts. Formulations differ in quality and quantity of cleaning agents.

Many of our readers have sports cars that they only drive occasionally. It’s important to find a fuel additive with a fuel stabilizer to keep the gas from oxidizing in the tank during extended periods of sitting. So which fuel system cleaner should you use?

Buying a high-quality cleaner

Fuel System Cleaner
Many fuel injector cleaners are strong enough to clean up deposits on a port fuel injector. However, most are no match for what lies in the combustion chamber.

The old saying, “you get what you pay for” is definitely true with fuel additives. If you buy a cheap fuel injector cleaner, it most likely won’t have the proper detergent package to do the job. If you get a high quality fuel system cleaner (i.e. higher quality and quantity of detergent) it will clean up these deposits in the entire fuel delivery system.

We were able to test two fuel system cleaners from Gumout and they did a good job of cleaning up my 2002 Subaru WRX 2.0-liter turbo engine. I did notice a difference in both improved performance and an increase in fuel mileage. These two products, fuel injector/carburetor cleaner and Multi-system tune-up from Gumout are available at most auto parts stores or on

Do you use a fuel system cleaner regularly or do you think it’s all the same?

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  1. I believe that fuel system must need to clean properly for better performance and mileage. Nowadays there are hundreds of fuel injector cleaners in the market. People always confused which one to choose for his or her car. Thanks to you for excellent tips to choose the right fuel injector cleaner. I am using lucas 10013 fuel treatment regularly.

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