For V6s, the most obvious clatter-maker is the cam gears, caused by a weak friction gear spring(s). It typically resonates (gets worst) around 1800RPM and is usually inaudible by 2000RPM.
A distinct tapping OTOH is typically caused by one or more collapsed HLAs (hydraulic lash adjusters). They'll tap for a bit until oil pressure pumps them back up again.
In either case, try switching to a Mobil 1 100% synth (5W30 for cold areas, 10W30 for warmer areas). Change it fairly often.
The friction gear springs can be replaced but the valve covers need to come off and the intake (left side)/exhaust (right side) cams must be removed from the engine to do the repair. Friction gear clatter is more of an annoyance/embarrassment than a serious engine problem.
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