What are the symptoms of a faulty spark plug in one cylinder?

[XavierAnn]

Damaged spark plugs can exhibit the following symptoms: difficulty starting, reduced power, excessive exhaust emissions, and increased fuel consumption. Steps to replace spark plugs: Open the hood, lift the plastic engine cover, remove the high-voltage ignition 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 such as leaves or dust and ensure thorough cleaning. 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 ignition wires in the firing order, then secure the cover. Spark plug replacement interval: Under normal maintenance conditions, replace spark plugs every 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type, so always refer to the owner's manual. The following standards can serve as a reference: Platinum spark plugs should be replaced at 40,000 kilometers, standard nickel alloy spark plugs at 20,000 kilometers, and iridium spark plugs at 60,000 to 80,000 kilometers.