How costly is it to repair a stripped out spark plug hole on a 2001 Chrysler tc ltd minivan with the 3.8 ltr v6. the stripped hole is on the back side of engine. is there a specialty tool for this job?

It isn't a bad job if you're handy with tools. They sell kits at most stores there are Helicoils and then solid inserts, all you do is tap the hole, out in the insert and then the spark plug. A tip to doing this, make sure the tap you get has vertical ridges for grease so the pieces are not falling in. Use a shop vac and vaccum out the debri from it as well. Another insert to consider is the TIME-SERT this is a solid thread bushing insert. http://www.timesert.com/html/sparkplug.html