why does my Ford Mustang S650 (2024-Present) have a check engine light with code P0301

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is on a flat surface and engage the parking brake.
• Disconnect the battery to prevent electrical shorts.

Tools Required:

• OBD-II scanner
• Spark plug socket
• Torque wrench
• Compression tester
• Multimeter
• Screwdrivers
• Pliers

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 1 by disconnecting the electrical connector and unscrewing any mounting bolts.
• Use a spark plug socket to remove the spark plug from cylinder 1.
• Inspect the spark plug for signs of wear, such as fouling or excessive gap.
• If necessary, replace the spark plug with an OEM equivalent, ensuring it is gapped correctly (typically around 0.030 inches for Mustangs).
• Reinstall the ignition coil, ensuring it is seated correctly.

3. Test and Replace Ignition Coil

• Use a multimeter to check the resistance of the ignition coil. Reference specifications for the expected resistance range.
• If the ignition coil is faulty, remove it and replace it with a new one, ensuring proper fitment.
• Reconnect the electrical connector to the ignition coil.

4. Inspect Fuel Injector

• Remove the fuel injector connector and inspect for corrosion or damage.
• Test the functionality of the fuel injector using a multimeter. If it does not meet specifications, replace the injector.
• Reinstall the new or inspected fuel injector, ensuring it clicks into place.

5. Perform Compression Test

• Remove the spark plug from cylinder 1 and insert the compression tester into the spark plug hole.
• Crank the engine for a few seconds and record the compression reading. Compare it to manufacturer specifications.
• If compression is low, further inspection of the piston rings or valves may be necessary.

6. Check for Vacuum Leaks

• Visually inspect vacuum lines and intake manifold gaskets around cylinder 1 for cracks or damage.
• Use a smoke machine or carburetor cleaner to detect any vacuum leaks while the engine is running.