how to fix P0303 misfire code on my Volkswagen Golf MK6 (2009-2014)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative terminal of the battery to ensure safety.
• Allow the engine to cool completely before starting work.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil from cylinder 3 by unscrewing the bolts and disconnecting the electrical connector.
• Use the spark plug socket to remove the old spark plug.
• Inspect the spark plug gap and condition; replace if worn or fouled.
• Install the new spark plug, ensuring to torque it to the manufacturer's specifications (typically around 22 ft-lbs).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Replace Ignition Coil

• If the spark plug replacement did not resolve the issue, proceed to replace the ignition coil.
• Tools Required: Socket set, torque wrench.
• Remove the old ignition coil as previously described.
• Install the new ignition coil onto cylinder 3 and secure it with bolts, tightening to the specified torque.
• Reconnect the electrical connector to the ignition coil.

4. Test Fuel Injector

• If misfire persists, check the fuel injector for cylinder 3.
• Tools Required: Fuel injector tester or multimeter.
• Disconnect the fuel injector connector and test for proper voltage and resistance.
• If faulty, replace the fuel injector by removing the injector rail and installing a new one.

5. Compression Test (if necessary)

• If all previous steps do not resolve the misfire, perform a compression test on cylinder 3.
• Tools Required: Compression tester.
• Remove the spark plug and screw in the compression tester.
• Crank the engine and record the compression reading. Compare with specifications (usually around 150 psi).
• If compression is low, further engine diagnosis may be necessary.