From the FSM, in this order: Nm, Ft/Lbs, In/Lbs.Trepnician, if you are going to tourque your plugs, you need to share the specs for everyone!! (you post in lb-ft and I'll convert them to N•m for those DI.net members who use them)
If the threads are stripped, yes. Helicoil™ is the most well known brand, although there are similar products that should work too. Measures need to be taken to keep the metal chips from falling into the cylinder (like putting grease on the tap), and directions need to be followed precisely.I saw something about an insert or thread fixer. Can this work for a 3.5?