What P0300 means
Diagnostic Trouble Code (DTC) P0300 stands for Random/Multiple Cylinder Misfire Detected. This is a generic OBD2 diagnostic trouble code indicating that the engine computer (ECU) has registered an operational anomaly in the powertrain (p) systems.
When this error registers, the ECU records a freeze frame of sensor data and lights up the Check Engine Light on your dashboard to notify the operator of a system fault.
Symptoms of OBD2 Code P0300
When code P0300 is active, your car might exhibit the following common symptoms:
- Flashing Check Engine Light
- Engine shaking, rough running, or heavy vibrations
- Strong smell of unburnt fuel from exhaust
- Lack of power and severe engine hesitation
Common Causes of Code P0300
Faults that trigger this code typically include:
- Cause 1: Worn spark plugs or bad ignition coils
- Cause 2: Vacuum leaks causing lean mixtures
- Cause 3: Low fuel pressure or clogged fuel filter
- Cause 4: Low engine compression due to mechanical wear
Can you drive with a P0300 code?
No. A misfiring engine dumps unburnt fuel into the exhaust, which can rapidly destroy the catalytic converter within minutes. If the Check Engine Light is flashing, pull over immediately and stop driving.
Expected Repair Cost Band
$50 - $150 (DIY plug/coil replacement) to $800+ if fuel delivery or engine compression issues are found.
Related Diagnostic Trouble Codes
If you have scanned multiple codes, see these related guides for troubleshooting context:
Frequently Asked Questions
A flashing Check Engine Light indicates a severe misfire that is actively damaging the catalytic converter. Stop driving immediately.
P0300 is a random misfire across multiple cylinders, while P0301 indicates a misfire isolated to Cylinder 1 specifically.