The spark plugs on a 1999 Ford Expedition 5.4L V8 are located on the top of the engine, under the ignition coils. To access the spark plugs, you will need to remove the ignition coils.
Here are the steps on how to remove the spark plugs on a 1999 Ford Expedition 5.4L V8:
1. Disconnect the negative battery cable.
2. Remove the air cleaner assembly.
3. Remove the ignition coil cover.
4. Disconnect the ignition coil connectors.
5. Use a spark plug wrench to remove the spark plugs.
6. Install new spark plugs.
7. Reinstall the ignition coils.
8. Reinstall the ignition coil cover.
9. Reinstall the air cleaner assembly.
10. Reconnect the negative battery cable.
Note: The spark plug gap on a 1999 Ford Expedition 5.4L V8 is 0.054 inches.
