ok, so i have a d16a6 bottom end, zc1 transmission, and z6 head and intake manifold. the issue; i let someone use my car for a day and didnt know that the put a bolt in the fit valve to "fix" the idle problem......... now the problem has obviously grown, and i am running like a subaru on three cylinders. the bolt is either somewhere in the head or in the intake manifold, but im guessing the head, because i removed the spark plugs and cylinder 4's electrode and prongs were completely smashed and gone, and found the electrode chilling just inside the combustion chamber. so im guessing that bolt is in the chamber as well, and was thrown into the spark plug, which destroyed it. now, whatever the spark plug screws into appears to be out of line where as cylinder 3doesnt appear that way. What could be my problem?? a buddy says its a bent valve, in which case i would just get a new head. and if i go that direction, thinking y8 head due to higher compression ratings, which obviously translates to more whp and torque. but to sum it up, i need help diagnosing the issue, and determining whether or not i should just get a new head, and if so, y8, or z6??