Tools required: Ratchet with various sockets, spark plug socket, torque wrench set to 33 lb-ft, 10 inch extension, PB Blaster, air compressor with blow gun attachment
Step 1: Make sure the engine is COLD. Let it sit overnight if need be. Some people argue the engine should be warm, but when it's warm the aluminum of the head expands and makes the hole the plug sits in tighter. In a cold engine situation the aluminum has not made the hole tighter and the metal threats on the plug have not expanded either.
Step 2: Remove all plugs and ignition coils to access the spark plugs. Once removed take the blow gun and blow the debris out of the holes.
Step 3: Use your torque wrench with the extension and spark plug socket and try the plugs. DO NOT TORQUE THE PLUGS OVER 33 FT LB AND GO VERY SLOWLY. DO NOT USE AN IMPACT. If it will move, move the plug about 1/8-1/4 turn and stop. With luck, one or two of the plugs will come loose completely and you can remove it.
Step 4: In the holes that still have the plugs in them, whether they were able to be partially turned or not, pour some PB Blaster, Seafoam deep creep, or some other penetrating fluid and let the plugs sit for 15-30 minutes.
Step 5: After waiting tighten the plugs back while not torquing over 33 ft lbs and then try loosening again. Repeat this process with stubborn plugs until they come out. DO NOT TRY AND FORCE A PLUG, IT WILL CRACK!
Step 6: Apply dielectric grease to top of plug and anti-seize to the threads if you want and reinstall plugs, again not torquing over 33 ft-lbs. Reinstall ignition coils and plug everything back in.
Check all connections of the ignition coils and injectors and start engine. Some smoke may come out from burning carbon buildup from the plugs and from the penetrating agent. If one of the plugs cracked, refer to Ford TSB 08-7-6 which illustrates how to use the motorcraft broken spark plug removal tool.