rangervr4.2

My 99 A8 has started making a noise that sounds like diesel clatter at low rpm's. Once I get to about 2000 rpm it goes away. The car has 145m miles. TB and water pump were replaced at 110m (po had the tb service done @90m, but the dealer did a crappy job). Any ideas would be greatly appreciated.
Thanks
Phil C

MP4.2+6.0

Easier: Maybe just sticky lifter issues or a secondary air pump. Could be a water pump bearing, or one of the drive belt or cam belt roller wheels or the tensioner wheels. LOng shots are other driven systems like power steering, air or alternator.

Really bad: Failing connecting rod bearings

Diagnose soon to eliminate the last one, or it goes from a regular rebuild to a really big parts bill or whole different block.

Most mechanics could eliminate most of these quickly and get to at least the right area before disassembling much, for example if it's in the belt area.

ex-a8drifter

I know this is really basic...I'm not insulting your intelligence, check oil level to be sure.

Always Overcharged

Fan/bearing?

rangervr4.2

It's not the oil level and I'm pretty sure it's not rod bearings or a fan bearing. The noise is faint at idle, increases until about 1400 rpm, then goes away. Any thoughts regarding the cam tensioner?
Thanks for all the feedback and input.
Phil