Common Symptoms
- Check engine light illuminated
- Rough idle or engine vibration
- Loss of power or hesitation during acceleration
- Poor fuel economy
- Engine stumble or jerking at cruising speed
- Strong fuel odor from exhaust
Most Likely Root Causes
- Faulty spark plug or ignition coil on cylinder 3
- Vacuum leak affecting cylinder 3
- Fuel injector clogged or failed on cylinder 3
- Low compression in cylinder 3
- Incorrect valve clearance or worn camshaft lobe
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Component Location
Cylinder 3 is typically the third cylinder from the front on inline engines or varies by manufacturer firing order on V-configuration engines.
Manufacturer Notes
Some manufacturers use coil-on-plug systems where cylinder numbering and coil location must be verified from service information before diagnosis.
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