Cylinder 3 Misfire Detected
The engine control module has detected that cylinder #3 is misfiring—meaning it's not combusting fuel properly or consistently. This causes incomplete power delivery, reduced efficiency, and potential damage to the catalytic converter if left unaddressed.
What You Might Notice
- Engine hesitation or stumbling during acceleration
- Rough idle or shaking at standstill
- Difficulty starting the engine
- Check Engine light illuminated
- Reduced fuel economy and sluggish performance
Most Common Causes
- 1
Faulty Spark Plug or Ignition Wire
A worn, fouled, or gapped spark plug in cylinder #3, or a damaged spark plug wire, prevents proper ignition and combustion. This is the most common cause of single-cylinder misfires.
- 2
Defective Ignition Coil Pack
A failing or dead coil pack for cylinder #3 cannot generate sufficient voltage to fire the spark plug. This is especially common in coil-on-plug ignition systems.
- 3
Faulty Fuel Injector
A clogged, leaking, or stuck fuel injector for cylinder #3 delivers too much or too little fuel, creating an improper fuel-air mixture that won't ignite reliably.
- 4
Low Compression or Mechanical Damage
Burned exhaust valves, worn piston rings, or head gasket leaks in cylinder #3 reduce compression, preventing complete combustion even with good spark and fuel delivery.
How to Diagnose It
- 1
Check Faulty Spark Plug or Ignition Wire — A worn, fouled, or gapped spark plug in cylinder #3, or a damaged spark plug wire, prevents proper ignition and combustion. This is the most common cause of single-cylinder misfires.
- 2
Check Defective Ignition Coil Pack — A failing or dead coil pack for cylinder #3 cannot generate sufficient voltage to fire the spark plug. This is especially common in coil-on-plug ignition systems.
- 3
Check Faulty Fuel Injector — A clogged, leaking, or stuck fuel injector for cylinder #3 delivers too much or too little fuel, creating an improper fuel-air mixture that won't ignite reliably.
- 4
Check Low Compression or Mechanical Damage — Burned exhaust valves, worn piston rings, or head gasket leaks in cylinder #3 reduce compression, preventing complete combustion even with good spark and fuel delivery.
How to Fix It
- 1
Inspect and Replace Spark Plug
Remove the spark plug from cylinder #3, check the gap and condition, and replace it with a new one rated for your vehicle. Ensure the plug is properly gapped according to manufacturer specs.
- 2
Test and Replace Ignition Coil
Inspect the ignition coil or coil pack serving cylinder #3 for cracks, burn marks, or corrosion. Use a multimeter to test coil resistance if possible, and replace if faulty.
- 3
Clean or Replace Fuel Injector
Remove and inspect the fuel injector for cylinder #3. Try professional fuel injector cleaning first; if the injector is permanently damaged or leaking, replacement is necessary.
- 4
Perform Compression Test and Inspect Valves
Use a compression gauge to test cylinder #3 pressure and compare it to other cylinders. If compression is low, have a mechanic inspect for burned valves, worn piston rings, or head gasket failure requiring engine disassembly.
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