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P0300

Random/Multiple Cylinder Misfire Detected

The engine computer has detected misfires in one or more cylinders, but not limited to a single cylinder. This usually means the engine is not burning fuel correctly because of bad ignition parts, fuel delivery problems, air leaks, sensor faults, or internal engine issues.

Severity4/5 High
Can I drive?⚠ With caution

You may be able to drive short distances, but the engine may run poorly, stall, or lose power. Continued driving can damage the catalytic converter and may make the vehicle unsafe in traffic.

DIY
$20–$300
Shop
$120–$1,500
Difficulty
intermediate

What It Means

P0300 means the powertrain control module has detected random or multiple cylinder misfires. Because the misfire is not isolated to one cylinder, diagnosis usually involves checking ignition, fuel, air metering, vacuum leaks, and mechanical engine condition. The code may appear with other misfire codes, fuel trim codes, or sensor-related codes that help identify the root cause.

Symptoms

Common Causes

1. Worn or fouled spark plugshigh
2. Faulty ignition coils, wires, distributor cap, or rotor where equippedhigh
3. Vacuum leak or unmetered air entering the enginehigh
4. Low or weak fuel pressure from pump, filter, or pressure regulator problemshigh
5. Defective mass airflow sensor causing incorrect air measurementmedium
6. Incorrect ignition timing or cam/crank sensor problemmedium
7. Improperly functioning EGR systemmedium
8. Defective throttle position sensor or throttle body issuemedium
9. Mechanical engine problems such as low compression, valve issues, or head gasket leakslow

Related Codes

FAQ

What does P0300 mean?

It means the engine computer detected random or multiple cylinder misfires.

Can a bad spark plug cause P0300?

Yes. Worn or fouled spark plugs are one of the most common causes.

Will P0300 clear itself?

It may clear temporarily if the problem goes away, but it will usually return until the cause is fixed.

Can I keep driving with P0300?

Only for short distances with caution. If the engine is shaking badly, stalling, or flashing the check engine light, stop driving and diagnose it right away.

Does P0300 always mean the ignition system is bad?

No. It can also be caused by vacuum leaks, fuel pressure problems, sensor faults, or engine mechanical problems.