What are the symptoms of poor spark plug ignition?

[GriffinLee]

Symptoms of poor spark plug ignition include: difficulty starting the car, low power, excessive exhaust emissions, and increased fuel consumption. Methods to determine if a spark plug is damaged: Remove the spark plug and observe its condition based on the following appearance colors. A normal spark plug's insulator skirt and electrodes should appear gray-white, gray-yellow, or light brown. If the spark plug has oil stains or deposits, the spark plug itself is not damaged. If the top of the spark plug shows blistering, black streaks, or similar phenomena. Symptoms of spark plug failure: difficulty starting the car, low power, excessive exhaust emissions, and increased fuel consumption. Steps to replace a spark plug: Open the engine hood, lift the plastic engine cover, remove the high-voltage distributor wires, and mark each cylinder's position to avoid confusion. Use a spark plug socket to remove the spark plugs one by one. While removing them, check for external debris like leaves or dust and ensure everything is cleaned thoroughly. Place the new spark plug into the spark plug hole, hand-tighten it a few turns, and then use the socket to tighten it further. Reinstall the high-voltage distributor wires in the firing order, then secure the cover.