how to fix Honda Accord 10th Generation (2018-2022) with a P0303 misfire

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and 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.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for wear or damage; replace if necessary.
• Install a new spark plug, tightening to the manufacturer's specified torque (usually around 13 lb-ft).
• Reinstall the ignition coil ensuring all connections are secure.

3. Check and Replace Ignition Coil

• If the spark plug is in good condition, test the ignition coil.
• Tools Required: Multimeter.
• Measure the resistance of the ignition coil; compare it against specifications in the service manual.
• If it is out of range, replace the ignition coil with a new one.
• Reassemble the ignition coil and ensure proper connection.

4. Inspect and Clean Fuel Injector

• If misfire persists, check the fuel injector for cylinder 3.
• Tools Required: Fuel injector cleaner, injector puller (if needed).
• Remove the fuel injector from cylinder 3 by detaching the fuel rail if necessary.
• Clean the injector using a specialized cleaner or replace with a new one.
• Reinstall the injector ensuring proper seating and connection.

5. Perform a Compression Test

• If all components are functioning, perform a compression test.
• Tools Required: Compression gauge.
• Remove all spark plugs and install the compression gauge in cylinder 3.
• Crank the engine and record the compression reading; it should meet specifications.
• If the reading is low, further diagnosis for internal engine issues may be needed.