You will need a special 16 mm wrench to remove spark plugs (with a rubber bushing to hold the spark plug).
For vehicles with a 1.6L Duratec engine, perform the following steps.
1. Remove the decorative engine cover (see Removing and installing the decorative engine cover).
2. Remove the high-voltage wire tips from the spark plugs.
3. Blow out the spark plug wells with compressed air to prevent dirt from getting into the engine cylinders when removing the spark plugs.
4. Remove the spark plug…
5….and remove it from the spark plug well.
NOTE: Inspect the spark plug and assess its condition by its appearance.
6. Use a round feeler gauge to check the gap between the spark plug electrodes. It should be 1.3 mm.
7. If the gap differs from the specified value, adjust it by bending the side electrode.
WARNING: Adjust the gap only by bending the side electrode. Any bending of the center electrode will cause the spark plug insulator to break.
8. Remove and check the remaining spark plugs in a similar manner.
9. When installing spark plugs, first screw them in by hand (with a wrench without a ratchet), and then tighten them with a wrench.
For vehicles with 2.0L and 2.3L Duratec-НЕ and 2.5L Duratec-V15 engines, perform the following operations.
NOTE: Although the Duratec-V15 engine cylinder head design is slightly different from the Duratec-HE engines, the spark plugs for all three of these engines are replaced using similar techniques.
1. Remove the decorative engine cover (see Removing and installing the decorative engine cover).
2. Remove the ignition coils (see Removing and installing ignition coils for duratec-he and duratec-v15 engines).
3. Blow out the spark plug wells with compressed air to prevent dirt from getting into the engine cylinders when removing the spark plugs.
4. Unscrew the spark plugs and remove them from the spark plug wells.
5. Check the spark plugs and adjust the gap in the same way as described above for the 1.6L Duratec engine (see steps 6 and 7).
6. When installing spark plugs, first screw them in by hand (with a wrench without a ratchet), and then tighten them with a wrench.
The full article is on the online resource (FORDBOOK)