Common Symptoms
- Check engine light illuminated
- Rough idle or engine misfire
- Reduced engine power or hesitation
- Poor fuel economy
- Engine stumbles or runs on three cylinders
- Increased hydrocarbon emissions
Most Likely Root Causes
- Faulty fuel injector on cylinder 4
- Damaged or corroded wiring harness to cylinder 4 injector
- Loose or poor electrical connection at injector connector
- Failed fuel injector driver circuit in PCM
- Chafed or shorted injector wiring
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Component Location
The cylinder 4 fuel injector is located in the intake manifold or cylinder head at the fourth cylinder position, typically numbered from front to rear.
Manufacturer Notes
Some manufacturers require PCM reprogramming or injector coding after injector replacement to ensure proper fuel trim adaptation.
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