P0300 means random/multiple cylinder misfire detected. Your engine's computer detected that several cylinders are misfiring — meaning the fuel-air mixture isn't igniting prope
Pull over safely — continued driving risks serious damage.
Your engine's computer detected that several cylinders are misfiring — meaning the fuel-air mixture isn't igniting properly in more than one cylinder. You'll usually feel shaking, rough idle, or a loss of power.
The most common cause. Plugs wear out every 30k–100k miles depending on type.
Coils crack with heat and age; one failing coil can cause multi-cylinder misfires.
Restricts fuel delivery to one or more cylinders.
Unmetered air leans out the mixture across cylinders.
Weak pump or clogged filter starves the engine.
Typically $100–$600
Spark plug replacement typically $100–$300; ignition coil(s) typically $150–$400. Estimates vary by vehicle. Costs are estimates and vary by vehicle, location, and shop.
If the check engine light is FLASHING, stop driving — continued driving can overheat and destroy the catalytic converter ($1,000+ damage). If it's steady, drive gently to a shop soon.
Typically $100–$600. Spark plug replacement typically $100–$300; ignition coil(s) typically $150–$400. Estimates vary by vehicle.
Pull over safely — continued driving risks serious damage.
The most common cause is worn spark plugs. The most common cause. Plugs wear out every 30k–100k miles depending on type.