This could apply to any engine, but i figure I would be specfic as to the car typein the title.   
A month or so ago my GF was driving back home from work when her car started having an issue.  I get there and find the front middle spark plug is completly out.  Wierd, but no big deal.  I go get my tools, put it in and trq it down.    
Today she is on the way to work when it comes out again.  I am at work so she can't get a hold of me.  She calls AAA.  They arrive and tell her "the spark plug is 2 small for the hole, and the hole has become stripped"  Interesting  theory... Sure enough however the spark plug well thread is stripped and the spark plug won't thread in.  I even went so far as to remove another plug and try it.   
I personally think AAA boy did something he shouldn't have..but I digress.   
I am now left with a stripped out middle bank.  I am assuming I will have to pull the head and either   
A.  Replace it. 
B.  Have someone weld it in some, and then retap.   
I believe this are aluminum heads for what that's worth.   
My hope in posting here is that someone will have a "shortcut"  so that I may cheat having to pull this motor all appart.   
TIA,   
Howard