Abodee,
Yup I got a piston stop to check my damper. My TDC mark is right on. But I do get a 10 degree fluctuation which leads me to figure I have a chain issue. Of course I am not experiencing the same problems. I think my issues are valve related. Especially due to the big swing on idle vacuum and even at higher RPM's. I am guessing a tight valve or two or worse burnt valves. I did have that severe pinging issue.
Boy this one is a real brain jerker.