Skip the auto shop - Our mechanics make house calls

Symptoms of a Bad or Failing Ignition Coil

ignition cable

Bad or Failing Ignition Coil Inspection

by a top-rated mechanic at your home or office

Ignition coils are an electronic engine management component that are a part of the vehicle’s ignition system. The ignition coil functions as an induction coil that converts the vehicle’s 12 volts into the several thousand that are required to jump the spark plug gap and ignite the engine’s air-fuel mixture. Some ignition systems will use one coil to provide the spark for all of the cylinders, however most newer designs use an individual coil for each cylinder.

As the ignition coil is the component responsible for generating the engine spark, any problems with it can quickly lead to engine performance issues. Usually a faulty ignition coil will produce a few symptoms that alert the driver of a potential issue.

HAVE SYMPTOMS OF CAR TROUBLE?
Get an $80 diagnostic
by a top-rated mechanic at your home or office.

Get a quote · Book an Appointment · Our expert mechanics come to you.

1. Engine misfires, rough idle, and loss of power

One of the most common symptoms associated with a faulty ignition coil is engine performance issues. As the ignition coils are among the ignition system's most vital components, an issue can cause spark to be compromised, which can quickly lead to performance issues. Faulty coils may cause the vehicle to experience misfires, a rough idle, a loss in power and acceleration, and a reduction in gas mileage. In some cases the performance issues may even result in the vehicle stalling.

2. Check Engine Light comes on

Another symptom of a potential issue with the vehicle’s ignition coils is an illuminated Check Engine Light. Faulty coils can lead to engine performance issues, particularly misfires, which will trip the computer and set off the Check Engine Light. The Check Engine Light will also be set off if the computer detects an issue with the ignition coil signal or circuit, such as when a coil burns out or shorts. An illuminated Check Engine Light can be caused by a wide variety of issues, so having the computer (scanned for trouble codes)[https://www.yourmechanic.com/services/check-engine-light-is-on-inspection] is highly recommended.

HAVE SYMPTOMS OF CAR TROUBLE?
Get your car fixed at your home or office.

Get a quote · Book an Appointment · Our expert mechanics come to you.

3. Car is not starting

A faulty ignition coil can also lead to a no-start condition. For vehicles that use a single ignition coil as the source of spark for all of the cylinders, a faulty coil will affect the operation of the entire engine. If the coil fails completely, it will leave the engine without spark, which will result in a no spark, no-start condition.

Problems with ignition coils are usually easy to detect as they produce symptoms that will be quite noticeable to the driver. If you suspect that your vehicle’s ignition coils are having an issue, have the vehicle inspected by a professional technician from YourMechanic to determine if any coils need to be replaced.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Still not sure about your car's issue?
Diagnose your car
What kind of issue are you experiencing?
Brakes are squeaking
Car is not starting
Car is overheating
Car is shaking (vibrating)
Fluids are leaking
Heating and A/C
Smoke or steam is coming out of the car
Warning light is on
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

Symptoms of a Bad or Failing Flexible Clutch Hose
Common signs include difficulty shifting, low clutch fluid, and feeling no resistance at the clutch pedal.
P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222...
How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...


Related questions

Q: Engine misfires and ticking sound on startup, coasting, and acceleration.

The noise in the engine may be from running with the ignition timing too far advanced from a malfunctioning mass air flow sensor. The mass air flow sensor could be giving false readings, which will cause the computer to compensate...

Q: Check Engine light is coming on

The problem may not be the Mass Air Flow or MAF. It could be an unmetered air leak, such as a torn intake duct or vacuum line. Check the ducts and make sure they are free from cracks or splits...

Q: ABS light blinks when the car is turned off

This is odd, since generally the ABS light should come on for a few seconds with the ignition ON. My suggestion is to have the system scanned for diagnostic trouble codes which serve as a starting point for further diagnosis....