We have a 01 6 cyl mustang with a eaton off a cobra on it. The kid has not tunned it and has the stock plugs in it.h: The car is spark knocking like crazy. I know it needs a tune but what plugs should it run. It only is running 2lbs of boost it will run more with stock crank pulley! This car is retarded but need to know what plugs to run.