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Powertrain fault code

P0300: Random/Multiple Cylinder Misfire Detected

Stop and check

If the engine light is flashing, stop driving: unburnt fuel can overheat and destroy the catalytic converter.

What P0300 means

The engine computer has detected misfires on more than one cylinder, or it can't tell which cylinder.

Common causes

  • Worn spark plugs or ignition coils
  • Vacuum leak
  • Low fuel pressure
  • Low compression

What to check first

  1. If the light flashes, park the car and have it towed or checked.
  2. Check the age of the spark plugs and coils.
  3. Scan for other codes stored with it.

P0300 on popular makes

P0300 on a Chevrolet

  • On high-mileage engines start with spark plugs and ignition coils, and look for a P0301–P0308 code naming the cylinder.
  • On GM V8 engines with Active Fuel Management (cylinder deactivation), lifter faults are a known cause of misfires; a workshop can check this.

P0300 on a Nissan

  • Ignition coils and spark plugs are the usual first checks.
  • If a lean code (P0171/P0174) is stored too, fix the air leak or fuel problem first: a lean engine misfires.

P0300 on a Ford

  • Ignition coils and spark plugs are frequent causes on Fords; check for a cylinder-specific code.
  • Swap the coil from a misfiring cylinder with a good one: if the misfire moves, the coil is faulty.

P0300 on a Toyota

  • Toyotas use a coil on each plug: swapping a coil to another cylinder shows whether the misfire follows it.
  • Old or poor-quality fuel and worn plugs are common on cars that have stood or have high mileage.

Get P0300 explained for your car: $2.99

  • P0300 explained in full for your make and model: meaning, how urgent, likely causes and what to check, in order.
  • A short personal note from us within 24 hours, or your money back.
  • Your own private report page you can save as a PDF or show your mechanic.

Read your car's codes yourself, free

Plug a cheap ELM327 OBD-II adapter into the port under the dashboard and open the scan tool: Chrome or Edge on a computer with a USB adapter, or Chrome on Android with a Bluetooth LE adapter. It reads and clears codes and shows emissions readiness. It does not work on iPhone.

Open the free scan tool

Need help with P0300?

Tell us your car and what it is doing with P0300. We reply by email with what to check first, in plain words. Free.

General guidance only, not a diagnosis. A qualified mechanic should confirm the cause before you replace parts.