P0300
Random/Multiple Cylinder Misfire Detected
Description
Random/Multiple Cylinder 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
- Engine misfiring or running rough
- Lack of power during acceleration
- Engine may stall or shut off
- Unusual engine vibrations
- Poor fuel economy
Diagnostic Recommendations
- Check all spark plugs and ignition coils for proper operation
- Inspect fuel injectors for proper spray pattern and flow
- Test compression in all cylinders
- Check for vacuum leaks in the intake system
- Verify fuel pressure is within specification
- Examine engine timing and timing chain/belt condition
Repair Cost Estimate
- Spark plug replacement (set of 4-8): $80-200
- Ignition coil replacement: $150-400 per coil
- Fuel injector cleaning/replacement: $200-800
- Engine compression test: $100-200
- Total diagnostic and repair: $300-2000
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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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