Meaning

A misfire localised specifically to cylinder 1. Unlike P0300 (random), the fault is on one identified cylinder.

Common causes

• Faulty spark plug or coil on cylinder 1
• Clogged or failed injector on cylinder 1
• Low compression on cylinder 1 (valves or piston rings)
• Damaged wiring or connector to the cylinder-1 coil or injector

Symptoms

• Check-engine light (flashing if severe)
• Rough idle
• Vibration and power loss
• Higher fuel consumption

Severity

What to do

1. Swap the cylinder-1 coil or plug with another cylinder and see if the misfire follows the part
2. Check the cylinder-1 injector
3. Measure compression on cylinder 1

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