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.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Ignition coil
- Spark plug
- Fuel injector
- Intake manifold
- Timing chain
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Worn spark plugs
- Vacuum leak affecting all cylinders
- Fuel pressure low
- Timing chain stretched (high mileage)
Possible 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
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
- Reduced-power or limp mode may occur
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.