I spoke with the Assistant Service Manager at my dealership late today and it appears the "mysterious" noise was identified

and corrective action is being taken. Apparently, the noise was coming from the lifters/tappets--
one of the "followers" was bad--that appears to have been what was causing the noise. The parts have been ordered--
the lifters and followers are all being replaced to be sure the problem is corrected for good. At least they didn't have to go into the motor but only removed the value cover to do the necessary work.
I should get my car back by the end of the week and then I can confirm the noise is gone for good after driving a few hundred or more miles. Guess I'll have to just wait and see if all is well... [8D]...keeping my fingers crossed that the "Five Star Dealership" guys did
[u]quality work</u> and my
[u]engine is now sounding normal</u>...
...[u]all the time</u>!