Common Symptoms
- Check engine light illuminated
- Rough idle or engine misfire
- Reduced engine power or hesitation
- Increased fuel consumption
- Black smoke from exhaust
- Engine may start hard or stall
Most Likely Root Causes
- Faulty fuel injector on cylinder 4
- Damaged or corroded injector wiring harness
- Short circuit in injector driver circuit
- Failed injector driver in PCM or ECM
- Corrosion or moisture in injector connector
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Component Location
Cylinder 4 fuel injector is located on the intake side of the engine at the fourth cylinder position in the firing order.
Manufacturer Notes
Some manufacturers use external injector driver modules that may fail independently of the main PCM and should be tested separately.
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