P0306

Cylinder 6 Misfire Detected

OBD-II diagnostic trouble code P0306indicates a fault detected by the vehicle's onboard computer. This code applies to all OBD-II compliant vehicles and should be addressed promptly to avoid potential engine or emissions system damage.

Severity Level 4 — Serious

This code indicates a serious issue that can cause noticeable driveability problems and potential engine damage if not addressed. The vehicle should be taken to a mechanic as soon as possible. Extended driving is not recommended.

Common Symptoms

• Flashing or steady Check Engine Light
• Engine vibration and rough running
• Loss of power and hesitation under load
• Poor fuel economy
• Unburnt fuel smell from exhaust

Possible Causes

• Worn or fouled spark plug on cylinder 6
• Faulty ignition coil or spark plug wire for cylinder 6
• Clogged or leaking fuel injector on cylinder 6
• Low compression — burnt exhaust valve, worn piston rings, head gasket leak on cylinder 6
• Intake manifold gasket leak at cylinder 6 runner
• Carbon buildup on intake valves (direct injection)

Common Fixes

• Replace cylinder 6 spark plug ($10-30 DIY, $80-150 shop)
• Test and replace coil/wire for cylinder 6 ($50-200)
• Clean or replace cylinder 6 fuel injector ($80-400)
• Compression test and repair ($1500-4000 for major engine work)
• Walnut blast intake valves (DI engines, $400-800)

Estimated Repair Cost

These are estimated costs based on generic repair data. Actual costs may vary depending on your vehicle, location, and labor rates.

Explore Repair Costs

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