Symptoms of a faulty ignition coil
-Loss of Power. This is one of the first symptoms of ignition coil failure.
-Check Engine Light On.
-Poor Fuel Economy.
-Backfiring.
-Misfiring Engine.
-Hard Starts and Stalling.
-Spluttering and Coughing Sounds.
-Jerking and Vibrating.
Engine misfires can be caused by a list of faults, but there are a few suspects that occur more than others. The primary villains are simple – spark or fuel – usually manifesting in spark plugs, plug wires, the coil(s) or the fuel-delivery system.