Tapping noise after not truck sat

I went on vacation for approximately a week. Came back today and started my tundra (5.7) and there was a terrible rattling noise on start up. It did get better but a hollow tapping/rattling noise is still present even after letting it run and driving up/down my driveway.

When revving engine, the engine noise over powers it and I cannot hear (or it goes away, unable to tell)

Not able to find much on Google other than the 1-2 second rattle on start up.
Any insight anyone?

Thank you

 

Pour in a qt of automatic transmission fluid and drive it gently. Hopefully the detergents will help clean up the sticky valve trains and timing chain tensioners. I'd probably drive it a couple of hours even if it quiets down before then. Good luck!

 

https://youtu.be/l2OAHImTgA8

This is addressed by the car care nut, it is valves that lost hydraulic pressure, he gives a sequence to correct that without any damage to your engine.