Cylinder 2 Misfire
P0302 is a cylinder-specific misfire code. The computer sees cylinder 2 slowing down compared with the rest of the engine.
A misfire can damage the catalytic converter if driven hard or ignored.
Common symptoms
- Rough idle
- Engine shake
- Hesitation
- Check engine light
- Raw fuel smell
Likely causes
- Spark plug wear
- Ignition coil failure
- Injector fault
- Vacuum leak
- Low compression
What to check before replacing parts
Swap the coil to another cylinder
Look for: A misfire that follows the coil confirms a bad coil; a misfire that stays on cylinder 2 means the coil is fine and the cause is elsewhere on that cylinder.
Inspect the spark plug condition
Look for: Sooty/black = rich, oily = oil intrusion, white/blistered = lean or overheating, cracked porcelain or wrong gap = replace. A clean tan color is normal.
Check injector operation on cylinder 2
Look for: No injector click/pulse, or flow noticeably different from the other cylinders, points to a clogged or dead injector rather than an ignition fault.
Review freeze-frame data
Look for: Note the RPM, load, and temperature when the code set. A misfire only under load or only cold narrows the cause toward fuel delivery or a cold-related vacuum leak rather than a worn part that would misfire everywhere.
Compression-test cylinder 2 if needed
Look for: Low compression relative to the other cylinders confirms a mechanical cause and means further parts-swapping on ignition or fuel won't fix it.
This page explains the generic P0302 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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