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IgnitionSeverity High: diagnose before driving on

P0300Random/Multiple Cylinder Misfire Detected

What it means

The ECU sees misfires on more than one cylinder, or on cylinders that change. Look for something that affects all cylinders, or several faults at once.

Symptoms

  • Rough running, shaking at idle or under load
  • Loss of power
  • Flashing check engine light

Common causes

  • Worn spark plugs or several weak coils
  • Vacuum leak or low fuel pressure (lean misfire)
  • Low compression or timing problem
  • Crankshaft sensor signal problems or contaminated fuel

What to check first

  1. Look at the per-cylinder misfire counters
  2. Check fuel trims and fuel pressure
  3. Run a relative compression test
Can I drive with P0300? Not recommended. P0300 can lead to stalling, limp mode or engine damage; diagnose it before driving further.
Practise it: Ignition coil, cyl. 3 in the engine simulator shows this fault in live data, tests and on the scope.Open in the simulator

Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.

How to test the parts behind P0300

Petrol fuel injector (port injection)Wiring, typical values, multimeter and scope testsIgnition coil (coil-on-plug)Wiring, typical values, multimeter and scope tests

Known engine problems that set P0300

1.2/1.4 TSI EA111: Cracked pistons on the high-output 1.4 TSIVolkswagen, Audi, Skoda, Seat · typically 80,000–180,000 km1.8/2.0 TFSI EA888: High oil consumption (piston rings)Audi, Volkswagen, Skoda, Seat · typically 60,000–160,000 km1.8/2.0 TFSI EA888: Carbon build-up on the intake valvesAudi, Volkswagen, Skoda, Seat · typically 80,000–160,000 km1.2 PureTech: High oil consumptionPeugeot, Citroën, DS, Opel · typically 60,000–160,000 km1.6 THP/Prince: Oil consumption and carbon build-upMini, BMW, Peugeot, Citroën, DS · typically 60,000–160,000 km1.2 TCe: High oil consumptionRenault, Dacia, Nissan, Mercedes-Benz · typically 40,000–120,000 kmTheta II 2.0/2.4: Carbon build-up on the intake valves (GDI)Hyundai, Kia · typically 80,000–180,000 kmMultiAir/TwinAir: MultiAir actuator failureFiat, Alfa Romeo, Lancia · typically 80,000–180,000 km1.6 GDI Gamma: Carbon build-up on the intake valvesHyundai, Kia · typically 80,000–160,000 km1.6 GDI Gamma: Oil consumption and piston or bearing damageHyundai, Kia · typically 80,000–200,000 km1.8 Hybrid 2ZR-FXE: Clogged EGR system, misfire and head gasket damageToyota, Lexus · typically 150,000–300,000 km

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P0300: questions and answers

What does P0300 mean?

P0300: Random/Multiple Cylinder Misfire Detected. The ECU sees misfires on more than one cylinder, or on cylinders that change. Look for something that affects all cylinders, or several faults at once.

What are the symptoms of P0300?

Rough running, shaking at idle or under load. Loss of power. Flashing check engine light.

What causes P0300?

Worn spark plugs or several weak coils. Vacuum leak or low fuel pressure (lean misfire). Low compression or timing problem. Crankshaft sensor signal problems or contaminated fuel.

How do you diagnose P0300?

1. Look at the per-cylinder misfire counters 2. Check fuel trims and fuel pressure 3. Run a relative compression test

Can I drive with P0300?

Not recommended. P0300 can lead to stalling, limp mode or engine damage; diagnose it before driving further.