Misfire isolated to cylinder 1. On the 981 flat-six, cylinders 1-3 form Bank 1.
SYMPTOMS
- Flashing or steady check-engine light
- Rough idle
- Hesitation
- Vibration
LIKELY CAUSES
- Faulty coil or plug on cylinder 1
- Failed injector
- Low compression
- Intake leak at that runner
DIAGNOSIS STEPS
- Swap the coil and plug to an adjacent cylinder and see if the misfire follows
- Test the injector
- Compression/leak-down test on the cylinder
RELATED PARTS
- Ignition coil
- Spark plug
- Fuel injector