P0300: Random/Multiple Cylinder Misfire Detected

Symptoms

• Rough idle and shaking at stops
• Hesitation or stumbling on acceleration
• Noticeable loss of power
• Check engine light flashing under load

Common causes

• Worn or fouled spark plugs
• Failing ignition coil packs
• Vacuum or intake manifold leak
• Clogged or leaking fuel injector
• Low fuel pressure or weak fuel pump

What to do?

Avoid hard driving while a misfire is active to protect the catalytic converter. Start with the basics: inspect spark plugs and coils, then scan for cylinder-specific misfire codes (P0301-P0308) to narrow the source. If no single cylinder is flagged, check for vacuum leaks and fuel pressure before replacing parts.