What are the signs that spark plugs need to be replaced?

[MarleyFitz]

Symptoms indicating that spark plugs need replacement: The car exhibits difficulties in starting, reduced power, excessive exhaust emissions, and increased fuel consumption. Severe spark plug damage may show signs such as blistering at the tip, black streaks, cracking, or electrode melting. Methods to determine if spark plugs are damaged: Remove the spark plugs and observe their appearance to assess their condition. A normal spark plug's insulator skirt and electrodes should appear gray-white, gray-yellow, or light brown. A properly functioning spark plug has a reddish-brown insulator skirt, with an electrode gap between 0.8-0.9mm and no signs of electrode burning. If the spark plug is covered in oil or deposits but is not damaged, it can continue to be used after cleaning off the oil and deposits. If the spark plug is severely damaged, showing blistering, black streaks, cracking, or electrode melting, the cause of the damage should be identified. After troubleshooting, replace the spark plug with a new one. Additionally, if the spark plug appears black as if smoked, it indicates the wrong heat range was selected or the air-fuel mixture is too rich, with oil creeping up.