How Do I Know If My Fuel Injectors Are Bad?

How do I know if my fuel injectors are bad?
June 4, 2023

Frequent driving often produces carbon and other deposits within your fuel system. This buildup can lead to dirty, clogged or leaking fuel injectors. When that happens, your engine isn’t getting the right amount of fuel, and you may notice decreased performance or other issues.

The Basics of a Fuel Injector

Your vehicle has an intricate system for maintaining the precise mix of air and fuel your engine needs to function at its best. These components and process steps include:

  • A fuel pump to deliver fuel from the tank to the fuel injectors.
  • Fuel injectors to spray fuel into the intake manifold or engine cylinders, where it mixes with air.
  • A combustion chamber to receive and compress the air-fuel mix and spur the chemical reaction powering your engine.

Since the system essentially forms a pathway between your fuel tank and your engine, it’s easy to see how dirty fuel injectors can affect the process.


What Are the Symptoms of Bad Fuel Injectors? 

Several bad fuel injector symptoms can alert you to a potential issue. 


If you’ve noticed vibrating sensations or delayed acceleration, a misfire could be the cause. Engine misfires can result in a temporary loss of power and are a common clogged fuel injector symptom. They occur when the injectors don’t provide the precise air and fuel mixture your vehicle needs at just the right time. Since the delivery and timing are off, the engine doesn’t burn fuel correctly. 

Rough Idle

Your engine should purr or even rumble — it’s not supposed to shake, sputter or stall when idling. Again, these sounds and issues result from an engine not getting the right combination of fuel and air. You may also notice dropping RPMs or uncommon noises while sitting in traffic or at a red light. 

Bad Gas Mileage

When your fuel injectors perform at their best, you’re more likely to get the fuel economy your vehicle’s manufacturer advertised. A sudden increase in fuel consumption can indicate dirty, clogged or leaky injectors — the fuel system’s controls will automatically send more fuel to the combustion chamber when it doesn’t receive enough to fire properly. 

A Flaky RPM Needle

Fuel injectors affect your dash’s RPM gauge. When they experience issues, you may see the tachometer jump around unpredictably in response to an incorrect fuel-air mix. With too much fuel, the engine surges and RPM increases despite the same load.

Won’t Start, or the Check-Engine Light Comes On

Failure to start may not always indicate fuel injector issues, but it can be in more severe cases. When no fuel hits the right cylinders, it’s impossible for the engine to execute its combustion. A check engine light remaining steadily lit or blinking is another common symptom of bad fuel injectors.

A Fuel Leak

If you notice the smell of fuel in your vehicle interior while driving, especially if any of the symptoms described above accompany the odor, your injectors may have a leak. Other signs indicating a possible leak include fuel pooling beneath the vehicle or on the injector exteriors.

A leaking fuel injector can create:

  • More emissions
  • Idling issues
  • More fuel consumption
  • Hard starting

Fuel leaks are a fire hazard, so it’s best to address them as soon as possible.


How Do You Clean Your Fuel Injectors?

Help head off bad injectors and related issues by using a fuel injector cleaner at each oil change.

A well-formulated cleaner contains solvents designed to clean the fuel system by mixing with the vehicle’s regular fuel source. The solvents help reduce the buildup in your fuel lines and injectors. Based on the formula and fuel style, the precise ingredients will differ. These products burn with the fuel in your running engine and cause no damage to the system. 

For diesel engines, Hot Shot’s Secret recommendations deep cleaning the injectors every 6,000 miles with Diesel Extreme. For gas engines, Gasoline Extreme is recommended every 10,000 miles to keep injectors clean and running smoothly. 


Choose Hot Shot’s Secret for Fuel Injector Cleaners

Hot Shot’s Secret proudly creates problem-specific solutions for vehicle owners, including our popular fuel injector cleaners. We base our products on years of scientific research and stand behind them — if they don’t perform the way we promised, you get a full refund. 

Shop online around the clock or reach out to a Hot Shot’s Secret team member online for expert advice and assistance.