TORKO

P0300 Random/multiple cylinder misfire detected

What P0300 means

The engine computer detects misfires by watching for small changes in crankshaft speed. P0300 means misfires are happening in more than one cylinder or cannot be pinned to a single one. That points to a cause that affects the whole engine, such as ignition, fuel supply or air leaks.

P0300 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.

At a glance

Severity
High
Typical repair cost
50–600 €
Workshop time
0.5–6 h
Repair difficulty
Medium
DIY possible
Yes
Check engine light
Yes
Affects emissions test
Yes
Limp mode possible
Yes

Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.

Symptoms

Common causes

  1. Worn spark plugs or failing ignition coils
  2. Vacuum leak (intake hose, gasket or PCV system)
  3. Low fuel pressure from a weak pump or clogged filter
  4. Dirty or faulty air flow sensor
  5. Mechanical problem such as low compression or incorrect timing

Can I keep driving with P0300?

Have it checked today or tomorrow and avoid hard acceleration. If the light is flashing, driving on can overheat the catalytic converter and lead to an expensive repair.

What to check first

  1. Check which cylinders show misfire counts in live data and whether other codes (lean, fuel pressure) are stored
  2. Inspect spark plugs and coils; replace plugs if they are worn or due
  3. Look and listen for vacuum leaks and check fuel trims
  4. Check fuel pressure and, if needed, compression on all cylinders

Related codes

Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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