OBD-II code · Powertrain (generic)
P0300 Random/Multiple Cylinder Misfire Detected
The ECU has detected misfires that are not concentrated on a single cylinder. The misfire monitor measures crankshaft acceleration after each combustion event; missing acceleration on multiple cylinders, or randomly across cylinders, triggers this code.
Is it safe to drive with P0300?
Drive gently and get it checked soon. If the check-engine light is flashing, stop driving: a severe misfire can overheat and ruin the catalytic converter.
Common causes
- Most likelyWorn spark plugs
- Most likelyVacuum leak affecting all cylinders
- PossibleFuel pressure low
- Less likelyTiming chain stretched (high mileage)
Symptoms
- Check engine light on or flashing
- Rough idle and uneven running
- Power loss, hesitation under acceleration
- Increased fuel consumption
- Possible smell of unburned fuel from exhaust
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–6 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Ignition Coil, Spark Plug, Fuel Injector, Intake Manifold, Timing Chain
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.