Slowly stopped??? Like it was laboring and couldn't keep up the momentum and then wouldn't restart? Or is was running slowly then suddenly quit?

I'm sorry but it sounds fatal.

If you have the time to mess around, start with a complete tune-up (you will eventually need the parts for a rebuild anyway). The oil you drain out will be a telling factor.

Cut open the old oil filter with a hack-saw (realize that the chips will get in there so don't freak if there is a small amount of steel "dust") you are looking in the pleats for trapped bearing material so it will be messy... Also, whatever accumulates in the bottom of the cover (the "dome").

If you get more than trace bits of "bright-stuff" or any large (bigger than dust) fragments you can bet the bottom end is done.

Checking the timing set for the source of the noise is still prudent as it is a known potential source of noise/failure to run. Also it is much easier to get to than the pan!

g'luck
--
Mike!