The ignition coil takes power from the battery and relays it to the spark plugs, which burns fuel, which makes your car run. If one or more of the ignition coils fail, your car’s ability to run efficiently will be greatly hampered. The degree to which, and the number of ignition coils that are failing, as well as the total number of ignition coils the car runs on, determine the severity of the car’s symptoms.
Symptoms of ignition coil failure may include a decline in fuel economy, change in exhaust, backfiring issues, misfiring issues, difficulty starting and issues with stalling. There are several different ways to diagnose an ignition coil failure issue mechanically, including checking the wires connecting to the spark plugs. If you test these wires and find that there is no power reaching the spark plugs, then this means that energy is not properly being converted and transferred by the ignition coil between the battery and the spark plugs. This is the most common way to diagnose an ignition coil failure.