Been having this rattling/clicking sound soon after I start it up after sitting overnight. It will die out and come right back & it only happens when idling or in park... It goes away after I drive for about 5mins
Video: https://imgur.com/a/1zTjDKq

 

Search the forum, been discussed many times.
It most likely is due to the injection systems, as this car has two, if gets quiet after warms up most likely not timing chain clatter.

 

I’ve had this same issue and thought it was timing, it does go away after car warms up or press the throttle at idle to get it up to temp, however I recently changed my spark plugs and got an injection fuel system cleanes and the sound went away. Not sure what the correlation was but just thought I’d share.

 

Sounds fine to me. This happens to my LS460 sometimes, but I haven’t noticed it since my last oil change.