ratling Engine bay ratling when idling

[Audi A6 tdi le]

Hi everyone, when idling and if I gently accelerate as the revs go down there is a plastic rattling sound from engine bay. The car pulls and drives fine, when warm also when idling there is a bit of vibration and once you rev up vibration goes away Any advice would be appreciated, thanks in advance 

2008 audi a6 2.0 tdi avant 

170k

Edited December 25, 2019 by Audi A6 tdi le
Mistaken error