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Check Engine Light Comes On And Off While Driving – What Could Be Wrong?

One way your car tells you something is wrong is through the signs and marks on your dashboard. So, if you're wondering what the issue is if the check engine light flashes on and off while you're driving, we did some research and found out what it is.

Misfires are the main reason a check engine light will flicker or blink. However, there are other reasons why this happens.

The blinking of the check engine light can also be caused by:

  • Faulty coils or spark plugs
  • Loose gas cap
  • Malfunctioning oxygen sensors
  • Defective EGR valve
  • Malfunctioning mass airflow sensor
  • Defective catalytic converter

Read on as we expound on the causes and how to determine the signs of these problems. We'll also discuss why it is essential to address issues with the check engine light. With that said, let's dive in!

Check engine light illuminated on dashboard, Check Engine Light Comes On And Off While Driving - What Could Be Wrong?

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Is It Important To Fix A Broken Check Engine Light?

The onboard diagnostics system in your vehicle, which keeps an eye on engine speed, fuel mixture, and ignition timing, includes the check engine light.

This light is activated when that system notices a problem it can't fix on its own.

The majority of the time, you can continue driving after it turns on without stopping to contact for assistance. However, you should immediately interpret the light as a signal to visit a mechanic.

Its significance can change whether the check engine light is steady or flashing.

An issue has been discovered when the engine check light is either solid or flashing. But if your engine check light is flashing, a significant problem needs your immediate attention.

To avoid severe damage, it is best to call a professional as soon as you notice a flashing light.

warning light engine in car dashboard

What Leads To Engine Misfiring?

An engine misfire could happen for a variety of reasons. As you already know, an engine needs the right amount of power from your car's cylinders to run smoothly. A misfire could happen if a cylinder stops generating power.

The following are causes of typical misfires:

  • Problems with the ignition
  • A fuel mixture imbalance
  • Low compression pressure

Women's hand turns the key to the car. Hands of the girl to take the keys to start the car engine

Problems With Ignition

It's typical for ignition parts to experience regular wear and tear, frequently resulting in spark-deficient plugs or incorrect ignition timing.

If your check engine light blinks, it may be because spark plugs and ignition coils require routine maintenance and replacement.

Fuel Mixture Imbalance

For cylinders to function correctly, fuel and air must be precisely balanced.

If there is too much air in the cylinder, an imbalance in the mixture can cause delayed acceleration or backfire, and if there is too much fuel, it can cause overheating and jerky running.

The components of the fuel system need to be extensively inspected to address these problems.

Low Compression Pressure

The right fuel combination in your cylinders will produce the right amount of pressure, and the pressure will be lost if there is a fuel leak or air leak.

As a result, the car may accelerate slowly, have poor power, or shake or jerk. Pressure drops may be caused by leaks in the head gasket, piston holes, damaged valves, or worn timing belts.

What Are The Signs That Your Engine Is Misfiring?

There are a few warning indicators to check for if you're not sure whether your engine is misfiring or not.

Pay attention to the following signs:

  • The vehicle vibrates when you are accelerating or idling.
  • Your car is stumbling or speeding up unevenly.
  • Losing power: frequently caused by an incorrect air-to-fuel ratio.
  • Your engine is making unusual noises.
  • A gas smell, which may potentially be a sign of a cylinder leak or other damage.

How Does A Bad Spark Plug Set Off The Check Engine Light?

Hand of the auto mechanic holding the old spark plug on blurred engine car

Spark plug wear can cause the check engine light on your car's dashboard to illuminate, alerting you to a potential issue. It can even be a check engine light that is flashing.

This is because faulty spark plugs may result in engine misfiring, which may turn on your check engine light.

The following are other indications of faulty spark plugs:

  • Erratic idling
  • Acceleration problems
  • Additional exhaust emissions
  • Trouble starting your car
  • Poor fuel economy
  • Poor vehicle performance

What Should You Do If You Have A Loose Gas Cap?

A loose or damaged gas cap is one of the most frequent reasons the check engine light illuminates.

The gas cap is crucial to your vehicle's fuel delivery mechanism. It keeps the system operating at its best by preventing gasoline from leaking out of the fuel tank and maintaining the proper pressure.

Usually, just tightening or replacing the gas cap will take care of this issue.

How Do You Know If You Have A Malfunctioning Oxygen Sensor?

Aside from your check engine light coming on, here are other signs that there is damage to your oxygen sensors:

  • Your car's oxygen sensor may malfunction if you spend more money on fuel than usual.
  • Your car can idle harshly or erratically if the oxygen sensor malfunctions. A damaged oxygen sensor can affect your engine's timing, combustion intervals, and other crucial operations. Additionally, you can observe halting or delayed acceleration.
  • A faulty oxygen sensor is the primary cause of emissions test failures. You might detect an unpleasant odor, akin to rotten eggs, in your car.
  • Your oxygen sensors may eventually become caked with combustion byproducts like lead, sulfur, gasoline additives, and oil ash. This prevents your sensors from transmitting information to the computer in your engine.

Every 60,000-90,000 miles on a vehicle less than 15 years old, you should have the oxygen sensors professionally updated to maintain engine efficiency and reduce pollution.

If your car is older, you should change the sensors every 45,000-65,000 miles.

What Causes Broken EGR Valves?

Most cars will circulate part of the exhaust gases back through the engine to meet strict pollution rules. Exhaust Gas Recirculation (EGR) valves are in charge of this.

The computer will detect a fault and activate the check engine light if the EGR valve malfunctions.

The old Exhaust gas recirculation in the engine compartment to reduce the carbon monoxide gas

The most typical issue is when carbon deposits on an EGR valve cause it to stick. The worst-case scenario is a completely blocked EGR valve and channels.

A stuck open EGR valve will cause a harsh, unsteady idle and stalling. When stopping after leaving the highway, a car frequently stalls.

The combustion temperature rises if the EGR system is blocked or the valve is jammed closed. Detonation and surging on light acceleration could result from this.

One of the causes of black smoke coming from a diesel engine is a malfunctioning EGR valve. In either scenario, the check engine light can also illuminate.

Although this component may appear a bit pricy, it's usually a simple fix and will guarantee that your engine runs appropriately once again.

What Are The Symptoms Of A Malfunctioning Mass Airflow Sensor?

A malfunctioning mass airflow sensor will exhibit symptoms similar to low fuel pressure from a faulty fuel pump, resulting in issues similar to low compression or low vacuum.

Car mass air flow sensor in the engine room. Car maintenance concept

The following are some of the most typical signs of a damaged mass air flow sensor:

  • Starting or turning over the engine is challenging.
  • Not long after starting, the engine stalls.
  • When running at idle or under load, the engine hesitates or lags.
  • Acceleration with pauses and jerks.
  • The engine sputters.
  • Idling that's overly rich or lean.

Take your car to a trained mechanic for a thorough computer diagnostic if you think the mass air flow sensor is malfunctioning.

A malfunctioning mass flow sensor will often produce a specific code during computer diagnostics, which is typically simple to identify with computer testing equipment.

What Is A Catalytic Converter And How To Tell If You Have A Defective One?

Exhaust installed in a modern car

One of the last lines of defense against vehicle-related air pollution is catalytic converters found in the exhaust system between the engine and the muffler.

They use porcelain beads and rare metals to convert unburned gas and nitrogen oxide into safe gases.

The following are some signs of a damaged catalytic converter:

  • Engine performance that is too slow
  • Decrease in acceleration
  • The smoky exhaust is dark
  • The exhaust has a sulfurous or rotten egg odor
  • Overheating underneath the car

A mechanic must determine when it's time to replace your catalytic converter because some of those symptoms can also be brought on by other components of the emissions system.

Our Final Words

Check engine light illuminated on dashboard

It's not a good idea to ignore a check engine light even if your car seems to be running smoothly and your mileage isn't declining. There is a problem, and it will probably get worse.

Additionally, if you reside in a region where cars must undergo recurring emissions inspections, your vehicle will likely fail the examination if your check engine light is on.

Depending on the light's illumination, issues like a misfire, a damaged spark plug, or a defective sensor could reduce fuel efficiency.

Made it to the end? Check out these helpful related posts!

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