how to diagnose Skoda Octavia with P0303 misfire code

Learn how to diagnose and fix P0303 cylinder 3 misfire in Skoda Octavia. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Replace Spark Plug and Ignition Coil

• Tools Required: Socket set, torque wrench, spark plug socket
• Remove the ignition coil from cylinder 3:
  1. Disconnect the electrical connector from the ignition coil.
  2. Unscrew the bolts securing the ignition coil and gently pull it out.
• Remove the spark plug from cylinder 3:
  1. Use a spark plug socket to unscrew and remove the spark plug.
• Install the new spark plug:
  1. Apply anti-seize compound on the threads (if recommended).
  2. Torque the spark plug to manufacturer's specifications (usually around 15-20 lb-ft).
• Install the new ignition coil:
  1. Position the ignition coil over the spark plug and secure it with bolts.
  2. Reconnect the electrical connector.

3. Test Fuel Injector

• Tools Required: Fuel injector tester or multimeter
• Disconnect the fuel injector connector for cylinder 3.
• Use a fuel injector tester to check the injector's resistance:
  1. Compare the resistance reading with specifications (often around 12-16 ohms).
  2. If out of range, replace the fuel injector.
• Reconnect the fuel injector connector.

4. Check for Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner
• Inspect all vacuum hoses and the intake manifold for leaks:
  1. Use a smoke machine to identify leaks around the intake manifold.
  2. Alternatively, spray carburetor cleaner around suspected areas while the engine is idling; listen for changes in engine speed.
• Repair or replace any leaking hoses or gaskets found.