P0300 — Random/Multiple Cylinder Misfire Detected
Drivable short-term, but fix now to avoid damage.
What P0300 means
P0300 means the engine computer detected misfires happening randomly across more than one cylinder, rather than in a single one. A misfire is when the air-fuel mixture in a cylinder doesn't ignite properly, so that cylinder loses power. Because it's not tied to one cylinder, the cause is usually something that affects the whole engine like fuel, vacuum, or ignition.
Common symptoms
- Check engine light on or flashing
- Rough or shaky idle
- Loss of power and hesitation when accelerating
- Engine stumbles or jerks while driving
- Worse fuel economy
Common causes
- Worn spark plugs or ignition coils
- Vacuum leak letting in extra air
- Clogged or dirty fuel injectors
- Weak fuel pump or low fuel pressure
- Faulty mass airflow (MAF) sensor
- Low engine compression
Typical repair cost
$100 – $600
Varies by vehicle and root cause.
Frequently asked questions
Can I drive with P0300?
Only short distances and gently. A steady light usually means you can reach a shop, but a flashing light means stop driving to avoid catalytic converter damage.
How much does it cost to fix a P0300?
It depends on the cause. A set of spark plugs runs about $100-$250, while coils or injector cleaning can push the bill toward $400-$600. A failed sensor or compression issue can cost more.
Is a P0300 serious?
Yes, it can be. Misfires send raw fuel into the exhaust and can overheat and destroy the catalytic converter, which is an expensive part. It's worth fixing promptly.
Why does P0300 hit multiple cylinders instead of one?
When several cylinders misfire at random, the problem usually isn't one bad coil or plug but something shared by all cylinders, such as a vacuum leak, low fuel pressure, or a faulty MAF sensor.