When a vehicle requires spark plug replacement, various noticeable abnormal symptoms typically manifest. The engine becomes difficult to start, often requiring multiple attempts to ignite, with particularly pronounced jerking during cold starts. At idle, the steering wheel and seats may exhibit noticeable vibrations, accompanied by abnormal knocking or detonation sounds from the cylinders. Insufficient acceleration during driving is a common symptom-especially when overtaking or climbing hills, where even full throttle application yields minimal power response, accompanied by an abnormal 10%-15% increase in fuel consumption. Upon disassembly and inspection, the spark plugs may show electrode gaps exceeding the standard 0.6-1.3mm range, severely worn and thinned electrodes, cracked ceramic insulators, or black carbon deposits around the electrodes. For standard nickel alloy spark plugs, replacement every 30,000 kilometres is recommended; platinum and iridium variants can last 60,000 and 80,000 kilometres respectively. Regular spark plug inspections can prevent ignition system failures and ensure the engine maintains optimal combustion efficiency.
