P0306
Cylinder 6 Misfire Detected
Ignition / misfire
Generic OBD-II
High
What it means
P0306 means the engine control module detected a misfire specifically in cylinder 6 — fuel isn't burning properly there, so the engine runs rough and loses power. The most common causes are a worn spark plug or a failing ignition coil on that cylinder. A sustained misfire can overheat and damage the catalytic converter, so fix it promptly.
High
Can I keep driving? Not for long — a flashing check-engine light means cylinder 6 is actively misfiring; drive as little as possible to avoid catalytic converter damage.
Common symptoms
What you'll notice
- Check-engine light on (often flashing during an active misfire)
- Rough idle, shaking, or vibration
- Reduced power and hesitation on acceleration
- Increased fuel consumption
Common causes
Most likely first
- Worn spark plug in cylinder 6Likely
- Failing ignition coil on cylinder 6Common
- Clogged or leaking fuel injector on cylinder 6Common
- Vacuum leak or low fuel pressure affecting that cylinderLess often
- Low compression in cylinder 6 (valve or ring wear)Less often
- Faulty ECM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data to confirm the miss is on cylinder 6.
- Swap the coil and plug with an adjacent cylinder — if the misfire follows, you've found it.
- Replace the worn spark plug and/or ignition coil for that cylinder.
- Test the injector for that cylinder and check fuel pressure.
- If it persists, run a compression test for mechanical causes. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0306?+
No — especially with a flashing light. An active misfire can quickly overheat and destroy the catalytic converter.
Can I just clear P0306?+
It returns within a few drive cycles until the plug, coil, injector, or compression issue on cylinder 6 is repaired.
Related codes
Often seen with P0306
Read & clear P0306 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX