how to fix P0300 random misfire code on Ford F-150 14th Generation (2021-2024)

Learn how to diagnose and fix P0300 random misfire in Ford F-150 14th Generation. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, compression tester, fuel pressure gauge.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Replace Spark Plugs

• Remove the engine cover if applicable.
• Using a socket set, remove spark plug wires or ignition coil packs.
• Extract spark plugs using a spark plug socket.
• Inspect each spark plug for wear, deposits, or damage. Replace if necessary.
• Ensure proper gap size according to manufacturer specifications (usually between 0.028-0.060 inches).
• Install new spark plugs and reattach ignition coils or wires, tightening to manufacturer torque specifications.

3. Check and Replace Ignition Coils

• Visually inspect ignition coils for cracks or damage.
• Using a multimeter, test primary and secondary resistance of the coils to ensure they are within specifications.
• If faulty, remove the ignition coils using a socket set and replace with new ones, ensuring proper connection and seating.

4. Inspect Fuel Injectors

• Remove the fuel injector connector and inspect for corrosion or damage.
• Conduct a fuel pressure test to ensure fuel injectors are receiving adequate fuel supply. The pressure should generally fall within the manufacturer’s specifications (consult service manual).
• If injectors are clogged, use a fuel injector cleaner or replace them as necessary.

5. Check for Vacuum Leaks

• Inspect all vacuum hoses for cracks or loose connections.
• Use a smoke machine or carburetor cleaner to identify leaks; any irregular idle changes indicate a leak.
• Replace or repair any damaged hoses or gaskets.

6. Perform Compression Test

• Remove all spark plugs for access.
• Insert the compression tester into the spark plug holes.
• Crank the engine to take readings. Ensure that all cylinders have a similar compression reading (typically 130-200 psi).
• If any cylinder shows significantly lower compression, further investigation into valve or piston ring condition is needed.