how to diagnose a misfire in my Ford F-150 Fourteenth Generation (2021-present)

Learn how to diagnose and fix engine misfire issues in Ford F-150 (2021-present). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, fuel pressure gauge, compression tester, multimeter.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to avoid any electrical shorts during repair.

2. Replace Spark Plugs

• Remove the engine cover if applicable.
• Use the socket set to remove the spark plug wires or coils.
• Extract the old spark plugs with a spark plug socket.
• Check the gap of the new spark plugs and install them, ensuring they are torqued to manufacturer's specifications (usually around 12-15 lb-ft).
• Reattach the spark plug wires or coils.

3. Inspect and Replace Ignition Coils

• If misfires persist after replacing spark plugs, inspect ignition coils.
• Disconnect the electrical connectors from the ignition coils.
• Remove the bolts securing the ignition coils using the socket set.
• Replace any faulty ignition coils with new ones, ensuring they are properly seated and connected.

4. Test Fuel System

• Connect the fuel pressure gauge to the fuel rail.
• Start the engine and observe the pressure; it should meet the specifications (typically around 30-45 psi for F-150).
• If pressure is low, check the fuel pump and filter for issues, replacing if necessary.

5. Check Compression

• Remove the spark plugs again for access.
• Insert the compression tester into the spark plug hole of each cylinder.
• Crank the engine for a few revolutions and record the pressure readings.
• Compare the readings to specifications; if low, investigate further for internal engine issues.