Ask Your Mazda Dealership: 6 Signs of a Faulty Ignition Coil

A smooth-running engine depends on the spark plugs, which in turn rely on the ignition coils. If one of your coils fouls, cracks, or malfunctions, the corresponding cylinder will no longer be able to fire properly. This misfiring robs the engine of power and can even damage your car. If you notice the following indications of a bad coil, have it repaired or replaced at your local Mazda dealer as soon as you can.

Ask Your Mazda Dealership: 6 Signs of a Faulty Ignition Coil

Dropping Engine Power

With all cylinders firing as they should, your car will be cruising along with as much power as you need. But if one bad coil prevents a spark plug and cylinder from doing its job, your engine’s power will be significantly reduced. You’re likely to notice this sudden loss of power when attempting to accelerate or when driving at speed on the highway.

Coughing, Sputtering Engine

When a coil begins to fail, the connected spark plug will be unable to produce the electricity required to ignite the fuel. As this spark plug misfires, the engine will cough, sputter, and shake. You may also hear strange banging sounds coming from the engine. It’s best to respond quickly to signs of misfiring, as the engine and elements inside the exhaust system can rapidly become damaged. 

Rough Idling and Stalls

Misfiring spark plugs make the ordinary smooth purr of an idling engine become rougher and louder. Your misfiring engine will clearly struggle when you pause at traffic lights and may even stall. Then, once stalled, you might find it difficult to restart with at least one coil failing to function properly. 

Falling Gas Mileage

When a bad coil causes misfiring, the fuel injector will continue to pump fuel into the cylinder. As this fuel is no longer being converted into mechanical power, your car will be traveling less far for each gallon of fuel it consumes. You’ll need to stop for gas more frequently. 

Black Smoke and Backfiring 

With a bad coil preventing the spark plug from sparking, the unburned fuel will collect inside the combustion chamber, coating the spark plug with sooty residue, thereby worsening the problem. This unburned fuel will also start to leak back into the exhaust pipes, wherein it may ignite, creating a loud bang and spewing black smoke from the tailpipe. 

Blinking Check Engine Light 

Fortunately, the check engine light will usually come to life on your dashboard as soon as one of your coils fails. It’s unwise to ignore this light; head to your local dealership without delay for repairs. 

Got a bad coil? Visit Royal Moore Mazda in Hillsboro, OR, to have it repaired or replaced today.  For over 50 years, we’ve been helping out the region’s drivers with excellent vehicles, competitive deals, and prompt, courteous customer care. 

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