5 Signs You Need An Ignition Coil Replacement
Here are some common signs of a faulty ignition coil:
1. Misfiring Engine
A bad ignition coil may cause your car to misfire while accelerating or, worse, stop your car while driving.
A misfire happens when a failing ignition coil generates an inconsistent voltage, affecting the spark plug and the combustion. As a result, a cylinder may fire incorrectly — causing spluttering or coughing noises.
Note: Misfires can affect the engine performance and damage engine components like the catalytic converter. So get your car checked out if your engine misfires.
2. Trouble Starting The Car
A failed ignition coil doesn’t deliver the required voltage for spark plugs to ignite the air and fuel mixture. As a result, you may find it difficult to start your car if multiple coils malfunction.
Car starting issues are common for many malfunctions, including a poor ignition coil connection or an electronic control module (ECM) issue. To confirm, get your car checked out by a mechanic.
3. Rough Idling
Bad ignition coils can also cause your car to run unsteadily at different RPMs (revolution per minute), even without your foot on the gas.
Sometimes, your car may have tiny vibrations when parked. These vibrations are gentler than misfires; however, they can shut down your running car in severe cases.
All of this is due to a bad coil generating power at irregular intervals — causing the fuel to burn inconsistently.
So, RPM fluctuations while driving or unusual engine sounds can point to ignition coil failure.
4. The Check Engine Light Turns on
Another sign of a bad ignition coil is the Check Engine light. It often illuminates when there’s a faulty ignition coil.
Remember that the Check Engine light can light up for many reasons, like a bad catalytic converter, a bad spark plug, or a loose fuel cap. So if your car supports the OBD 2 system, use an OBD 2 code scanner or a multimeter to confirm what’s wrong.
If it’s an ignition coil issue, it’ll likely read engine light codes from Code P0350 to Code P0362, depending on the faulty cylinder in your car.
For example, if there’s an issue in your first cylinder’s ignition coil or circuit, the OBD 2 code scanner will read Code P0351 (Ignition Coil ‘A’ Primary/Secondary Circuit Malfunction).
Note: The OBD 2 scanner will read other codes too (if any) that aren’t related to the ignition coil.
5. Increased Fuel Consumption
One of the early signs of an ignition coil failure is increased fuel consumption.
A faulty coil won’t be able to create enough electric spark for the spark plugs, resulting in reduced engine power. So to compensate, the car injects more fuel into the combustion chamber, affecting your gas mileage.
Note: Fuel consumption is difficult to spot. To identify significant changes, you can drive your car at regular intervals and distances. Or just call a mechanic if you suspect increased fuel consumption.