how to fix P0304 misfire code in Volkswagen Golf Eighth Generation (2020-present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the vehicle's negative battery terminal to ensure safety.
• Allow the engine to cool before starting any work.

2. Replace Spark Plug

• Remove the engine cover if applicable.
• Disconnect the ignition coil connector for cylinder 4.
• Remove the ignition coil using a socket set.
• Remove the spark plug using a spark plug socket.
• Inspect the old spark plug and replace it with a new one, ensuring the gap is set to specifications (consult the owner's manual for gap size).
• Reinstall the ignition coil and reconnect the connector.

3. Replace Ignition Coil

• If the spark plug replacement does not resolve the misfire, replace the ignition coil.
• Remove the ignition coil as described in the previous step.
• Install the new ignition coil and reconnect the wiring harness.
• Ensure all connections are secure.

4. Check Fuel Injector

• If the ignition components are fine, inspect the fuel injector for cylinder 4.
• Disconnect the fuel injector connector.
• Remove the fuel rail if necessary, following the manufacturer’s procedure.
• Replace the fuel injector if clogged or malfunctioning.
• Reassemble the fuel rail and reconnect the fuel injector.

5. Conduct Compression Test

• If misfire persists, perform a compression test on cylinder 4.
• Remove the spark plug for cylinder 4.
• Insert the compression gauge and crank the engine to get a reading.
• Compare the compression value to manufacturer specifications; replace the piston rings or cylinder head gasket if low compression is found.