Looking for some help. Working on a 02 Mazda Tribute with the 3.0 V6 DOHC. 160k miles. Noticed that the engine will squeal/rattle intermittently when at higher rpms. The squeal is more prevalent when the engine is cold. I have researched this complaint and found multiple answers. I have tried running the engine with the serpentine belt off for a very brief time. Noise still remains. I found a youtube video by Fordtechmakuloco explaining how the cam caps will loosen over time. I removed the valve covers tonight and made sure all cam caps are still torqued to 89 in/lbs. Found no issues. Did a quick check on timing chain slack while i had the valve covers off and does not appear to be loose either. Anyone have any other ideas on what to check next? Thanks!!