P0302: Cylinder 2 Misfire Detected

What it means

Misfires concentrated on cylinder 2. Diagnostic approach is identical to P0301 — swap the suspect coil or plug with a known-good cylinder and see if the misfire follows.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The engine control module estimates each cylinder's contribution from crankshaft acceleration after combustion. P0302 sets when the misfire monitor identifies cylinder 2 as repeatedly producing weak or missing combustion.

Common causes

Most likely first.

1. Ignition coil for cylinder 2 failed
2. Spark plug for cylinder 2 worn or fouled
3. Cylinder 2 injector clogged

Symptoms

• Check engine light on or flashing
• Rough idle and uneven running
• Power loss, hesitation under acceleration
• Increased fuel consumption
• Possible smell of unburned fuel from exhaust

How to diagnose it

1. Read freeze-frame data and misfire counters to verify cylinder 2 is the affected cylinder and identify when the fault occurs.
2. Inspect cylinder 2's spark plug, ignition coil, connector, and wiring for wear, fouling, damage, or a poor connection.
3. If the ignition design permits, swap cylinder 2's coil with another cylinder and see whether the misfire follows the coil.
4. Check the cylinder 2 injector connector and wiring, then test its operation and fuel delivery using the manufacturer's procedures.
5. If the fault remains on cylinder 2, test compression and mechanical condition against the manufacturer's specification.

Common fixes

• Replace a worn or fouled cylinder 2 spark plug.
• Repair a loose or damaged cylinder 2 ignition connection.
• Replace the cylinder 2 ignition coil if the misfire follows it during a swap test.
• Clean or replace the cylinder 2 injector if testing confirms a delivery fault.
• Repair cylinder 2's mechanical fault if compression testing identifies one.

Can I keep driving?

A flashing check engine light means stop driving as soon as it is safe; a cylinder 2 misfire can overheat and damage the catalytic converter. If the light is steady and symptoms are mild, keep driving limited and avoid hard acceleration until the cause is found.