P0303
Cylinder 3 Misfire Detected
Description
Cylinder 3 Misfire Detected. This powertrain diagnostic trouble code covers the engine, the fuel and ignition systems, emission control and the transmission.
OBD Codes Details
Possible Causes
Worn spark plugs, failed ignition coil, faulty injector, low compression in a cylinder
Solution
Read misfire counters per cylinder, inspect plugs and coils, swap the coil and injector to a neighbouring cylinder, run a compression test
Symptoms
- Rough idle or engine shaking at idle
- Check engine light flashing or illuminated
- Noticeable loss of power during acceleration
- Engine hesitation or stumbling
- Increased fuel consumption
Diagnostic Recommendations
- Inspect spark plug and ignition coil for cylinder 3
- Check fuel injector 3 for clogging or electrical failure
- Test cylinder 3 compression and leak-down
- Inspect wiring and connector for cylinder 3 coil/injector
- Check for vacuum leaks near cylinder 3 intake runner
Repair Cost Estimate
- Spark plug replacement (single): $20-50
- Ignition coil replacement (single): $100-250
- Fuel injector replacement (single): $150-350
- Compression/leak-down test: $100-200
- Total diagnostic and repair: $150-1200
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Fact-checking completed
Verified by:
Pavel Volkov
Created:
Information verified against official sources
Official Sources
Society of Automotive Engineers
Official OBD-II diagnostic trouble codes standard (SAE J2012)
Automotive engineering standards organization
International Organization for Standardization
International standard for vehicle diagnostic systems
International standards for automotive diagnostics
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