Have been enjoying my recently aqcuired 2004 Mustang GT --- up until today! I bought this car a few weeks ago (approximately 134,000 miles on it) --- figured I'd better change the spark plugs (not having any idea how long they'd been in there).
Started at the right front (Cylinder #1). Everything going fine until I got to Cylinder #3. The plug in #3 wasn't tight --- didn't need to be "broken loose", just spun right out. The spark plug looked pretty nasty compared to the other two I'd already removed, with black crap on the ceramic body of the plug (which I assume must be blow-by from the cylinder). Not wanting to acknowledge what I already feared, I applied anti-seize to a fresh new plug and attempted installation. Not happening --- no threads to accept the new plug. Aaahhhrrrrgggg!!! [I didn't actually say Aaahhhrrrgggg --- I said some really profane stuff.]
Went on and did the rest of the spark plugs --- no problems. All "broke loose" with a feel I expected and all them felt right when I torqued them at 160 inch-pounds.
So, the damage is done --- just have to fix it. My first thoughts were that the cylinder head will HAVE to be removed to fix this. But, maybe there are other workable options?? This is a fairly common occurance on these heads?? What do you suggest??