Ignition

P0300 — Random or Multiple Cylinder Misfire Detected

Severity: medium Drive with care, to a shop

What P0300 means

The engine control module watches crankshaft speed through the position sensor and notices when cylinders fail to burn their fuel properly. P0300 is set when misfires are random or spread across several cylinders rather than tied to one. Clean combustion needs a good spark, the right air-fuel mixture and adequate compression.

Symptoms

  • Check engine light on or flashing
  • Rough, shaky idle
  • Hesitation or stumbling when accelerating
  • Loss of power
  • Poor fuel economy
  • Fuel smell from the exhaust
  • Engine may stall

Possible causes

  1. Worn or fouled spark plugs
  2. Failing ignition coils or damaged coil wiring
  3. Low fuel pressure from a weak pump or clogged filter
  4. Clogged or faulty fuel injectors
  5. Vacuum or intake leaks from the manifold or cracked hoses
  6. Faulty sensors such as MAF, crankshaft, camshaft or oxygen sensors
  7. Mechanical problems such as low compression or incorrect valve timing

How to diagnose

  1. Read all codes and the freeze frame data to see the speed, load and temperature when it set
  2. Check per-cylinder misfire counters to see if one cylinder stands out
  3. Inspect spark plugs, coils, connectors and wiring
  4. Swap a coil or plug between cylinders and see whether the misfire follows
  5. Test fuel pressure and injector operation
  6. Look for vacuum leaks with a visual check, smoke test or fuel trim data
  7. Check MAF readings and crankshaft and camshaft sensor signals
  8. Run a compression test and verify timing

Common fixes

  • Replace spark plugs as a set
  • Replace faulty ignition coils or repair the wiring
  • Service the fuel system: filter, pump, injector cleaning or replacement
  • Fix vacuum leaks by replacing damaged hoses or gaskets
  • Replace the failed sensor
  • Perform engine repairs for compression or timing faults

P0300 on different brands

Ford · manuals
Ford uses the P0300:00 format on its 2024-2025 gasoline engines to indicate a general or specific cylinder misfire; it describes the monitor condition detected, not a confirmed failed part.

Questions and answers

What does P0300 mean?

The ECM detected misfires in several cylinders or in a random pattern. Spark plugs, coils, fuel delivery and air leaks are the usual culprits.

Can I drive with P0300?

With a steady light, only carefully and a short distance to a shop. With a flashing light, do not drive, because the catalytic converter can be ruined.

What should I check first?

Start with the spark plugs and ignition coils, then look for vacuum leaks and check fuel pressure. Freeze frame data and misfire counters help narrow it down.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.