Spark plug replacement interval and misfire: rough idle fixes

“Spark plug replacement interval” and “engine misfire” are paired searches. Iridium and platinum plugs last longer than older copper types, but they still wear and foul.

Typical intervals

Many modern petrol engines specify 60,000–100,000 km for long-life plugs. Turbo and direct-injection engines can foul earlier with short-trip use. Always follow the vehicle schedule when it is shorter.

Symptoms of worn plugs or coils

• Rough idle or shaking at traffic lights
• Hesitation on acceleration
• Flashing check-engine light under load
• Higher fuel consumption

Booking the job

Ask for plugs and a coil check if one cylinder misfires. On some engines access is labour-heavy, so a confirmed slot matters. Reserve service time on CarFix and mention misfire codes if you already scanned the car.