P0305: Cylinder 5 Misfire Detected
Can you still drive? Not recommended if the check engine light is flashing. A flashing CEL means severe misfires that can damage the catalytic converter. If the light is steady, drive minimally to a repair shop.
What Does P0305 Mean?
Code P0305 indicates that the ECM has detected a misfire in cylinder 5. The crankshaft position sensor monitors rotational speed and the ECM identifies the misfiring cylinder by detecting a deceleration in crankshaft speed during the power stroke of that specific cylinder. On V6 and V8 engines, cylinder 5 location varies by manufacturer — consult your service manual for the correct cylinder numbering for your engine.
Need to read your codes?
An OBD-II scanner lets you read and clear diagnostic trouble codes from your vehicle's computer. Most scanners work with any car made after 1996.
Browse OBD-II Scanners on AmazonCommon Causes
- Worn spark plug on cylinder 5
- Failed ignition coil on cylinder 5
- Faulty fuel injector on cylinder 5
- Low compression on cylinder 5
- Vacuum leak near cylinder 5 intake port
Symptoms
- Check engine light on or flashing
- Rough idle
- Vibration felt through steering wheel or seat
- Loss of power
- Increased exhaust emissions
Diagnostic Steps
- 1Inspect and replace spark plug on cylinder 5
- 2Swap ignition coil from cylinder 5 to another cylinder and see if misfire follows
- 3Check fuel injector operation on cylinder 5 using a noid light or stethoscope
- 4Perform a compression test on cylinder 5 and compare to other cylinders
- 5Check for vacuum leaks near the intake manifold at cylinder 5
- 6Inspect spark plug wire or coil boot for damage
Recommended Parts & Tools
ignition coil
spark plug wire set
compression tester
Estimated Repair Cost
| Type | Estimated Cost |
|---|---|
| Total Repair Cost Range | $50 - $1000 |
| Parts Only (DIY) | $50 - $200 |
| Labor (1-3 hrs @ $100/hr) | $100 - $300 |
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Frequently Asked Questions
Is cylinder 5 misfire common?
On V8 engines, cylinder 5 is one of the more common misfiring cylinders because it is often farther from the ECM and can have longer wiring runs. On some Ford V8s, cylinder 5 coil failures are particularly common.
Can I just replace one spark plug?
While you can replace just one, it is recommended to replace all spark plugs at the same time since they wear at similar rates. If only one plug is bad, it may indicate a deeper issue like a failing coil.
Community Fix Reports
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