Just pulled valve covers found 2 broken head studs. One broken stud found in valve cover, there is no sign of the other. I find it hard to believe that my pre-purchase inspection that included a valve adjustment and head stud check did not show this 8 months ago. The one stud may have broke while in my possession, but the other with no remains had to be there.
No visible signs of valve train issues. I will do leak down test and pull passenger side valve covers later this week. The head studs do not explain the miss/backfire. To mad to look at it right now. Thanks everyone for your insight. Any advise you can give is appreciated.