here are instructions for how to change the plugs. ive done a ton of 4.6 motors so here is what ive found best
tools required
-5/8 spark plug socket
-3/8 ratchet
-3", 6", 9" extension
-3/8" universal joint type connector
-7mm socket
-flat screwdriver
-gap checker
-bottle or tube of anti seize
-tube of dialetric grease
-compressed air
-fender covers
steps
ENGINE COLD, BEST TO DO IN MORNING AFTER SITTING OVERNIGHT
1. raise hood and put fender covers on car
2. take off intake hose with screwdriver, place on ground in front of car
3. use 7mm socket to take off bolts holding coils on top of each plug. put them on ground near intake hose, i leave in order, but ir doesnt matter they are all the same. to unplug them just kinda squeeze and pull
4. use compressed air to blow off inside the spark plugs holes with plugs still in.
5. start on one side using the spark plug socket, i start on the drivers side, but thats my weird thing i do. and pull out all the plugs. they might be hard to pull out, and they might creak a little, its normal. just go and pull all the plugs out, and put them down in order. at this time and check the gap and closely inspect them, again personal thing, im an OCD perfectionist.
6. get the new plugs and gap them, if they need to be gapped. i then put a little dab of anti sieze on the threads and use a paper towel to spread an even layer over the threads(OCD i know).
7. i then put a cleaner soaked paper towel down the threads and clean them out a little
8. i then put the plugs in using the socket and an extension, without a ratchet, i turn them until they are finger tight.
9. i then follow with a ratchet and tighten a 1/16th of a turn on all, then go back and do another 1/16th
10. i then take all the coils and clean the tops and inspect them for rips or wear.
11. put dabs of dialectric grease on all the coil boots. i get the tube and bend it and make 2 circles around(ya ya OCD).
12. pop the coils on all the plugs, press firmly until they look like they are flush with the intake for the bolts.
13. put in the bolts for the coils and hand tighten all, then follow with a ratchet about 1/8th of a turn.
14. put the air intake hose back on and tighten, you can also use a 8 or 10mm socket(forget which one offhand) and tighted with that.
15. i then usually wash off the motor and get all my fingerprints off.
16. start the motor and let the car idle for a minute, then start revving it progressively getting higher, listening to the motor. i bring it back to idle.
17. while idling, i take off the fender covers and close the hood, i then wipe off and put away all my tools and take off my latex gloves and wash my hands.
18. i then take the car around for a drive and see how it feels, should feel a little stronger and idle and accelerate smoother.
Whenever i work on a car i always wear latex gloves. and i try to wear pants like warmups or dickies type that wont scratch the paint. i also wear glasses normally, but ill usually wear safety glasses over them cause stuff getsin behind my glasses. the gap on the stock plugs should be around .054". i personally use Autolite 764's and change them every year. you can use other plugs, but the autolites are 1.18 a piece from pep boys, and even cheaper at wal-mart.
bdcardinal
, super easy to replace, you will notice a missing. I just started unplugging coil packs to figure out which one was bad, actually changed it in Ford parking lot 
