how to diagnose a misfire code P0301 in my Ford Mustang S650 (2024-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface with the engine off and cool.
• Disconnect the battery to prevent electrical shock.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, dielectric grease
• Remove the ignition coil from cylinder 1 by unscrewing the retaining bolts.
• Carefully pull out the spark plug using a spark plug socket.
• Inspect the spark plug for signs of wear or fouling; replace if damaged.
• Install the new spark plug, torquing to manufacturer specifications (usually around 13-15 lb-ft).
• Apply dielectric grease to the ignition coil boot to prevent moisture intrusion.

3. Inspect and Replace Ignition Coil

• Reinstall the ignition coil onto the new spark plug.
• If the ignition coil shows signs of failure during inspection, replace it with a new one.
• Reconnect the electrical connector to the ignition coil.

4. Fuel Injector Check

• Tools Required: Fuel injector cleaner, multimeter (if testing electrical components)
• If the fuel injector is suspected to be faulty, remove it from cylinder 1.
• Test the fuel injector for resistance using a multimeter; compare with specifications.
• Clean the fuel injector using a fuel injector cleaner or replace it if necessary.

5. Compression Test

• Tools Required: Compression gauge
• Reinstall the spark plug and ignition coil temporarily.
• Remove the fuel pump fuse to prevent fuel delivery.
• Perform a compression test on cylinder 1; record the pressure readings.
• Compare the readings with the manufacturer’s specifications; replace engine components if readings are low.