Disconnect power to the ignition module.
Are the wire connectors and multi-pin connectors securely connected to the ignition coil and control unit? Loose spark plug wires can become slightly elevated in the contact sleeves due to the heating of the trapped air, which can result in misfiring. Loose spark plug wires can cause leakage currents and uncontrolled sparking.
Check the ignition coil housing for cracks or burns caused by spark breakdown.
Quick and easy: To remove the multi-pin connector, simply press in the tension clamp (arrow)
Is there good contact between the terminals and the spark plug connectors? They should not be oxidized.
Check the ignition wires, the insulation should not be worn or frayed. Replace wires with signs of wear or melting immediately. If the ignition wire is defective, the spark may jump off before the spark plug (the path of least resistance!) - you can hear this by clicking sounds in the engine compartment.
Remove salt and lime deposits from spark plug wires.