2002 4.6 spark plug blew out and Ford wants $800+ just to check it. The service guy said the problem with these years was the metal make up in head. Newer don't have the problem...
Question 1 - Is that true?
Question 2 - Cheaper to replace the head from Rock Auto???
Question 3 - How had to replace the head, do I have to remove the intake and top of engine???

 

Yes problem on several years worth of models from that era. Read much more about it here-

http://www.blownoutsparkplug.com