An Introduction to Cleaning Fuel Injectors

March 20, 2025

5 min read

March 20, 2025

5 min read

If your car was built after 1990, it has some version of electronic fuel injection, and that means it has fuel injectors. They’re robust little valves that meter and squirt gas at precise intervals so your engine always has the optimum air-to-fuel ratio. Over time, they can get dirty or clogged.

If your car has dirty fuel injectors, it lets you know. It might run rough, misfire, hesitate, lose power, see a big drop in fuel economy, stall, or fail to start. None of those things are good, but they’re pretty easy to solve if the issue is indeed the fuel injectors. The symptoms of clogged or dirty fuel injectors can be caused by a bunch of issues. However, it isn’t always a quick diagnosis.

If your car isn’t showing signs of bad fuel injectors, it probably isn’t worth getting them cleaned. That’s particularly true if you drive your car often, run good quality fuel, and change your fuel filter somewhat regularly.

Symptoms of Dirty Fuel Injectors

A close-up view of a fuel injector spraying atomized fuel-air mixture in six directions. — Fuel injectors must spray a finely atomized mixture of gasoline and air into the cylinder for proper combustion.

Dirty fuel injectors cause rough idle, misfires, hesitation on acceleration, loss of power, and poor fuel economy. In some cases, your engine can stall out. When an injector gets dirty or clogged, the onboard computer senses a lean cylinder and sends more fuel to compensate. If the injector isn’t spraying fuel properly or can’t move the fuel through, the engine runs less efficiently and uses more gas.

At the same time, your car loses horsepower. You could notice it being slow to accelerate or having trouble passing or maintaining speed. Watch for a wandering tachometer needle, and listen and feel for vibrations.

Are there hiccups at idle? Are there any other out-of-the-ordinary noises? You might also get a check engine light when the computer senses a cylinder not firing properly.

Again, the symptoms of bad fuel injectors can be caused by other issues. If you are unsure, use an OBDII reader to check diagnostic codes before buying new parts.

Don’t Clean Your Fuel Injectors Too Early

A driver removes a green nozzle from a service station pump. — The best gasoline contains detergents to prevent clogging. There’s a reason why some brands cost more than others.

There’s no set interval for fuel injector cleaning, and the health of your injectors is dependent on a bunch of factors. If you use high-quality gas and don’t let your car sit for a long time, your injectors should be healthy for 100,000 miles or more. Regular fuel and air filter changes also boost the longevity of your fuel injectors.

Modern gasoline that contains ethanol attracts water over time. Gas that sits in the fuel system can get watery and cause small parts to rust. That can clog a fuel injector. Does your car sit for a long time with gas in the lines? Are you lax about fuel filter maintenance? Do you run cheap, low-octane gas? Don’t be surprised if you are cleaning your injectors sooner and more regularly.

The rule of thumb is to clean fuel injectors at 60,000 to 90,000 miles. Those intervals can be premature. A better rule is to clean the fuel injectors when your car shows symptoms of dirty injectors and you have ruled out other possible issues.

Cleaning Your Fuel Injectors

A set of six OEM Pentastar V-6 fuel injectors, displayed on a wood surface. — A set of six OEM Pentastar V-6 fuel injectors sells for under $100.

The good news is that cleaning your fuel injectors could be as easy as running a bottle or two of fuel system cleaner through your engine over the course of a couple of fill-ups. The bad news is that it usually isn’t that simple.

To do the job properly and thoroughly, you should remove the fuel injectors, run them through an ultrasonic cleaner, and then run a cleaning agent through them while using a power source to pulse the injectors. If that sounds complicated, messy, and dangerous, that’s because it is. Things get worse without the right equipment.

eBay Motors sells plenty of tools that are designed to clean and test fire fuel injectors safely. There are several options for electronic fuel injection and direct injection applications. But the tools are expensive. They’re hard to justify if you’re going to clean your injectors once.

Alternatively, it could be worth replacing your fuel injectors altogether. Use the eBay Parts Finder - opens in new window or tab. to find and price injectors for your specific vehicle. A complete set might only cost $100. That’s less than the cost of a cleaning.

Since you’re dealing with fuel under a fair amount of pressure, it’s critical to get high-quality replacement parts. The Parts Finder helps you narrow the search down to original equipment manufacturer (OEM) or OEM-equivalent parts easily. Each manufacturer uses its own suppliers, so look for names like ACDelco for GM products, or Denso for Toyotas.

How Much Cleaning Fuel Injectors Costs

Eight Bosch fuel injectors and packaging, displayed on a white surface. — Replacing dirty fuel injectors with a fresh set of name-brand injectors is the least expensive solution, if you’re ready to take on the task.

Unless your injectors are worn out and need to be replaced, there are no costs for parts. To clean your fuel injectors, you will need a bottle of fuel system cleaner, which is about $20. However, if things are dirtier, proper fuel injector cleaning tools can run from $250 to $600.

At a shop, you can expect to pay somewhere between $100 and $250 to get fuel injectors cleaned. That’s not the cheapest fix, but the shop rate is usually more cost-effective than purchasing the tools to do the job on your own. If you’re looking for a cost-friendly DIY, replacing your injectors is a better bet.

About the author

Aaron Richardson

Aaron learned early on that it's easier to be decent at a bunch of stuff than great at one thing, which led neatly to a career as a writer. He has been an automotive writer, a newspaper editor, and a business reporter, and has always worked on his own cars and bikes. When he isn't writing stories, he's wrenching on a '74 BMW 2002 or riding a motorcycle.

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This article is meant to provide general guidance only. Automotive maintenance, repair, upgrade, and installation may depend on vehicle-specifics such as make and model. Always consult your owner's manual, repair guide for specific information for your particular vehicle and consider a licensed auto-care professional's help as well, particularly for advance repairs.