Failing ignition coils or plugs can cause sputtering, rough idle, hesitation on acceleration, misfires, and a check engine light.

If one of your ignition coils is bad, it is a good idea to replace the plugs to prevent future problems. Great for fixing those rusted / corroded connection.

Sure, a failing ignition coil can cause various symptoms in a vehicle. The ignition coil is responsible for converting low voltage from the battery into high voltage needed to spark the spark plugs. When it starts to fail, it can exhibit several signs:

• Misfiring Engine: A common symptom is engine misfires or a rough running engine. You might feel the vehicle jerking or hesitating during acceleration.
• Difficulty Starting: A weak or failing ignition coil might cause difficulty starting the engine. You might notice extended cranking or the engine not starting at all.
• Decreased Fuel Economy: An inefficiently firing spark plug due to a failing ignition coil can lead to decreased fuel economy.
• Check Engine Light: A faulty ignition coil can trigger the check engine light on your dashboard. The car's computer might detect misfires or other related issues.
• Engine Stalling: In more severe cases, a failing ignition coil can cause the engine to stall, especially when idling or at low speeds.
• Increased Emissions: A failing ignition coil can result in increased emissions due to incomplete combustion.