What causes & how expensive is the fix, for a noticeable and persistent ticking

Hello, I've seen this before and it seems to be a pattern failure with these engines. I can't say for sure, but the last time I saw it, the camshaft and rockers in the back of the bank of cylinder head becomes worn and noisy. This could be due to lack of lubrication from maintenance or even a design issue. The repair would require removal of the valve cover for inspection and ultimately could involve major repair work including cylinder head removal. Certainly, seek local guidance instead of my hearsay -- but I have definitely seen it. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops