how to troubleshoot P0301 misfire code on Ford Mustang S550 (2015-2023)

Solution

1. Preparation

• Gather all tools and parts required for the repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent any electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil on cylinder 1 by unfastening bolts or clips.
• Carefully pull the ignition coil out and inspect the spark plug for wear or fouling.
• If worn, replace the spark plug with a new one, ensuring it is gapped correctly according to manufacturer specifications (usually around 0.030-0.035 inches).
• Reinstall the ignition coil and secure it properly.

3. Check and Replace Ignition Coil

• If the spark plug is in good condition, test the ignition coil for electrical resistance using a multimeter.
• If the ignition coil is faulty (out of spec), replace it with a new coil compatible with the Mustang S550.
• Ensure correct installation and secure connections.

4. Inspect Fuel Injector

• Remove the fuel injector from cylinder 1.
• Tools Required: Fuel line disconnect tool, socket set.
• Use a noid light to check for injector pulse while cranking the engine.
• If the injector is not firing, replace it with a new one.
• Reinstall the fuel injector and reconnect all necessary fuel lines.

5. Perform Compression Test

• Attach a compression tester to cylinder 1 and crank the engine.
• Tools Required: Compression tester.
• Compare the reading with the manufacturer's specifications (typically 120-180 psi).
• If the compression is low, further investigation is needed for potential issues like valve problems or head gasket failure.