P0306
P0306 Cylinder 6 Misfire Detected
P0306 is a generic OBD2 powertrain diagnostic trouble code for cylinder 6 misfire detected. The code identifies the system or circuit the engine computer flagged, but diagnosis still depends on vehicle symptoms, freeze-frame data, and related codes.
How urgent is P0306?
Misfires are urgent if the check engine light flashes. Raw fuel can overheat and damage the catalytic converter.
Common symptoms
- Check engine light
- Engine shake
- Rough idle
- Hesitation
- Loss of power
Likely causes
- Spark plug wear
- Ignition coil failure
- Injector issue
- Vacuum leak
- Mechanical compression problem
What to check before replacing parts
1
Read freeze-frame data
2
Swap ignition coil or plug if cylinder-specific
3
Inspect plug condition
4
Check fuel trims
5
Compression-test if ignition and fuel checks pass
Use the code with symptoms
A code points at the system, not always the failed part. Add your vehicle, mileage, symptoms, and whether the check engine light is steady or flashing so the AI diagnostic can narrow the next step.