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All codes/P0300

P0300

Random/Multiple Cylinder Misfire Detected

High severity

Your engine's computer has detected that one or more cylinders are not firing correctly, but it can't pinpoint a specific cylinder, or multiple cylinders are misfiring randomly.

The powertrain control module (PCM) has detected that multiple cylinders are misfiring or that the misfire is not specific to a single cylinder.

Common causes

  • Vacuum Leaks

    Leaks in vacuum lines, intake manifold gaskets, or PCV system can cause unmetered air to enter, leading to a lean condition and misfires across multiple cylinders.

    high

    Typical part cost: $50-300

  • Faulty Spark Plugs, Ignition Coils, or Wires

    Worn spark plugs, failing ignition coils, or damaged spark plug wires can lead to inconsistent or absent spark, causing misfires.

    high

    Typical part cost: $100-600+

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First things to check

  1. 1Check for other related codes (e.g., P0171/P0174 for lean conditions, specific cylinder misfires).
  2. 2Inspect spark plugs, ignition coils, and wires for wear or damage.

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Tools you may need

Already have a compatible scanner? Use it. If not, a Bluetooth OBD2 adapter can help you confirm engine codes and check supported live sensor data before replacing parts.

Illustration of a Bluetooth OBD2 adapter, not a product photo

Basic checks

Veepeak OBDCheck BLE

A Bluetooth LE adapter for reading standard engine codes and supported live data.

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Illustration of a Bluetooth OBD2 adapter, not a product photo

Regular diagnostics

vgate iCar Pro BLE 4.0

A Bluetooth LE adapter with an automatic sleep feature for routine code and sensor checks.

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Illustration of a Bluetooth OBD2 adapter, not a product photo

Another option

OBDLink CX

A Bluetooth LE adapter to consider when comparing supported vehicles and diagnostic apps.

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Illustrations shown, not product photos. Check vehicle, phone and app compatibility before buying. These adapters do not guarantee access to ABS, airbags or manufacturer-specific systems. Clearing a code does not repair the fault and can reset emissions readiness monitors.

As an Amazon Associate, Wrenchify earns from qualifying purchases. This supports the app at no extra cost to you.

Related codes

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Frequently asked questions

Why is my Check Engine Light flashing with a P0300?

A flashing Check Engine Light means the misfire is severe enough to potentially damage your catalytic converter. Unburnt fuel entering the exhaust can overheat and destroy the catalyst, which is a very expensive repair.

Can a P0300 code be caused by bad gas?

Yes, contaminated or low-quality fuel can certainly lead to misfires across multiple cylinders, triggering a P0300 code. If you suspect bad gas, try filling up with premium fuel from a reputable station once the tank is low.

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