how to diagnose a misfire on cylinder 4 in my Acura MDX YF3 (2022-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Spark Plug

1. Remove the engine cover (if applicable) using a socket set.
2. Detach the ignition coil connector for cylinder 4.
3. Remove the ignition coil using a socket and wrench.
4. Unscrew the spark plug using a spark plug socket.
5. Inspect the spark plug for wear; replace it if necessary with a new OEM or equivalent spark plug.
6. Apply anti-seize compound on the threads of the new spark plug.
7. Install the new spark plug and torque to manufacturer specifications (typically around 13-15 lb-ft).
8. Reinstall the ignition coil and reconnect the connector.

3. Replace Ignition Coil (if necessary)

1. If the ignition coil appears damaged, remove it as per the previous step.
2. Install the new ignition coil, ensuring it is seated properly.
3. Reconnect the ignition coil connector.

4. Test Fuel Injector

1. Remove the fuel rail (if necessary) to access the fuel injector for cylinder 4.
2. Use a multimeter to check the resistance of the injector (should be within the manufacturer’s specifications).
3. If faulty, replace the fuel injector with a new OEM part.
4. Reinstall the fuel rail and ensure all connections are secure.

5. Verify Compression (if misfire persists)

1. Remove the spark plug from cylinder 4 and install the compression tester.
2. Crank the engine and read the compression value; compare it to manufacturer specifications (typically around 180-210 psi).
3. If compression is low, investigate potential causes such as valve issues or head gasket failure.