how to fix Honda Civic 11th Generation (2022-Present) P0303 misfire code?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down before beginning work.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 3 using a socket set.
• Take out the spark plug using a spark plug socket.
• Inspect the spark plug for wear or damage; replace if necessary.
• Install a new spark plug (use OEM specifications for gap size).
• Reinstall the ignition coil and ensure it is seated properly.

3. Check and Replace Ignition Coil (if needed)

• If the spark plug is fine, test the ignition coil with a multimeter (check resistance).
• If it’s out of specification, replace the ignition coil for cylinder 3.
• Reinstall the ignition coil and reconnect the electrical connector.

4. Inspect and Clean Fuel Injector

• Remove the fuel injector connector from cylinder 3.
• Use a fuel injector cleaning kit or service to clean the injector.
• If cleaning does not resolve the issue, replace the fuel injector.
• Reconnect the fuel injector connector.

5. Perform Compression Test

• If issues persist, perform a compression test on cylinder 3.
• Remove the spark plug and install the compression gauge.
• Crank the engine and record the compression reading.
• Compare readings to manufacturer specifications; if low, further engine diagnostics may be necessary.