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Symptoms of a Bad Ignition Coil & Ways to Fix Them

Internal combustion engines, the most common vehicle on the road today, run on fuel and electricity.

The ignition coil provides the electrical element to the equation in modern cars. If your ignition coil is damaged, your engine won’t function properly. So it’s crucial to understand the signs of a malfunctioning ignition coil.

A vehicle’s engine performance depends on the ignition coils’ health and performance.

As a result, a malfunctioning ignition coil could be to blame for your engine’s poor performance. And since your car’s entire performance and running capability depends on ignition coils, for your convenience, we outlined four symptoms of a bad ignition coil and how to fix them. Read the article to learn more!

Ignition Coil-What Does It Mean

Before we start, let’s acquaint ourselves with the concept of the ignition coil in case you are new to it. It will be helpful to understand what an ignition coil means and how it functions before we look more closely at any potential ignition coil issues.

An engine can be started with the assistance of an ignition coil, also called a spark coil. The ignition system must have it as a crucial component.

Although the car battery only has twelve volts, the spark plug needs thousands of volts to start the engine.

An ignition coil functions as a miniature transformer, converting the twelve volts from the automobile battery into the necessary thousands of volts. The ignition coil’s energy is required for the spark plug to produce the spark needed for combustion.

No car in the world will start if there isn’t combustion.

4 Symptoms of a Bad Ignition Coil

While only one ignition coil will be discussed in this article, most engines must have a minimum of four, sometimes arranged in a coil pack. Your car’s performance may suffer if your ignition coils aren’t working properly.

Which is why it’s critical to watch out for the warning signs of a damaged ignition coil. Listed below are the four crucial symptoms of a bad ignition coil.

1. Trouble Starting the Engine

A malfunctioning ignition coil or many bad ignition coils may cause trouble starting your car’s engine.

The majority of modern engines feature numerous ignition coils. If you are facing difficulties starting your car frequently, the ignition coil might be the ultimate reason, and such a symptom shouldn’t be avoided. However, it might be one of the many reasons your car or vehicle isn’t starting.

Various issues might make it challenging for a car, and thus, difficulties starting the engine aren’t enough to prove an ignition coil issue.

But nevertheless, we recommend that you call a mechanic or check your ignition coil after seeing such a symptom.

2. Stalling/Misfiring of the Engine

If a car or vehicle is halting or accelerating very quickly, then we can assume that there is something wrong with the ignition coil and that it should be checked.

The misfire, in particular, indicates that one of the engine’s cylinders is not firing properly. And may produce sounds like sputtering or coughing. Your car or vehicle may even experience a little more vibration than usual, which isn’t normal.

When the engine is working at full power, there is a higher chance of misfires, which can also produce emissions. Because of this, greater emissions and a gas-like odor emanating from the exhaust can be signs of a faulty ignition coil.

However, as mentioned before, this can be one of the many reasons your car or vehicle’s engine is stalling or misfiring. Hence, to say with certainty that the issue is with the ignition coil may not be wise. Because of the malfunctioning ignition coil, erratic sparks from the spark plug might also cause the automobile to stall.

As a result, you should have a thorough checkup of your car or vehicle to see if the ignition coil is the main issue or not behind the misfiring engine.

3. Low Fuel Efficiency

Your automobile may have a defective ignition coil if you discover that it covers less mileage than usual with a full tank.

This occurs because the system within your car will attempt to make up for the underpowered spark plugs (caused by the malfunctioning ignition coil) by injecting extra fuel. This implies that fuel leaks may also be an indication of a problematic ignition coil.

4. Check the Engine Light

The check engine light’s purpose is to alert you to an issue with the vehicle’s engine. The check engine light may detect this and switch on if you have an ignition coil issue while driving.

Compared with the other signs we’ve covered, you must never overlook the check engine light, but several different engine issues might cause it.

So make sure you have looked for the check engine light, as it may clearly indicate something is wrong with the ignition coil.

How To Fix A Bad Ignition Coil

If you spot any of the symptoms mentioned above, it would be wise to replace your ignition coil, as that is the only optimal solution for your vehicle’s better performance.

It is simple to replace ignition coils because most have plug-and-play designs. If your car has coils of this type, even a newbie can manage the replacement without help. Nevertheless, certain coils are challenging to reach.

However, if you complete the work yourself, you only have to pay for the parts. In most automobiles, replacing ignition coils costs between $40 and $300 in components, even though their cost might vary greatly.


Overall, the ignition coil is essential for your car as it is technically responsible for your car’s performance and the core reason for how your car even functions. And we hope that the four symptoms we listed above about a bad ignition coil and how to fix it will help you a lot!

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