My friends 94 pickup 22RE engine is only running on 3 cylinders because she stripped the spark plug or broke it off in the head. I was considering buying her truck for a couple hundred dollars and fixing the spark plug problems and reselling it, or maybe just helping her fix it and sell it. So my question is do have to pull the head to do a heli coil? Also Ive never done a heli coil which is a concern.Is it hard? should I take the truck to a machinist? The motor doesnt have many miles and its the original not rebuilt so I would like to leave the head alone if possible. The rest of the truck is pretty nice still.Any help is appreciated