how to diagnose P0301 misfire code in Ford Explorer Fifth Generation (2011-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the engine is cool and disconnect the negative battery terminal.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Compression tester
• Multimeter
• Fuel injector tester (if needed)

2. Replace Spark Plug and Ignition Coil

1. Remove the engine cover (if applicable) by unbolting it.
2. Disconnect the wiring harness from the ignition coil of cylinder 1.
3. Remove the ignition coil using a socket set, noting the torque specifications when reinstalling.
4. Remove the spark plug using a spark plug socket and inspect it for wear or fouling.
5. Install a new spark plug, ensuring it is gapped according to manufacturer specifications (usually around 0.054 inches).
6. Install a new ignition coil and reconnect the wiring harness.

3. Check Fuel Injector

1. If the misfire persists, check the fuel injector for cylinder 1.
2. Disconnect the fuel injector electrical connector.
3. Use a fuel injector tester to check for proper operation.
4. Clean or replace the fuel injector if malfunctioning.

4. Conduct Compression Test

1. Remove the spark plug from cylinder 1.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine to take a compression reading.
4. If compression is below specifications (typically 130-150 psi), further engine diagnostics may be needed.

5. Reassemble and Test Drive

1. Reassemble any components removed during the repair.
2. Reconnect the negative battery terminal.
3. Start the engine and ensure it runs smoothly without misfires.
4. Take the vehicle for a test drive to confirm the repair.