OK - I now have the engine partially disassembled and am looking for some guidance before going too far.

I have manifolds removed, fan and shroud are out fo the way fuel lines removed, valve cover off, CC module off etc.. preparing to remove head and see if I can find the source of the knocking.

What should I look for in a vacuum pump to determine if it may be knocking?

How loose can a timing chain be, also why can I not find a master link on the chain? If I am not going to replace the chain, do I need to split it in order to remove the head.

When I cycle the motor by hand I get this wired creaking sound (like an old box spring) but only seems to be on exhaust stroke for #1 and #2??? Otherswise I do not see, feel or hear any other strange noices...

What size Torx is on the head? T60 was the largest I have.