9-3 Aero Cabrio – Phantom clapping…

Hello Saab community, have a 2003 Aero-Cabrio and with it a “gespenstische” problem: if I drive with the left rear wheel over – even small – floor waves, Gully cover etc. there is (feeled) from the back left a pitiful tinkering noise – but not always (!) … so let’s go to the buddy on the lifting stage – all wacked through, knocked, shaken (not stirred) – NIX! boot cleared out – nothing that could clap in it… .. Saab Werkstatt (Kaiser Fischbach) does everything – RATLOSITY and more lively rattles… Did one of you have such a thing? In the opinion of all “experts” it can’t be something important – but it is megalysed and messed up the whole Cabriovergügen…