Toyota Repair: noise underbody, good luck jack, rear struts

Question
only when it is cold outside, like now, there is a noise from uner the car. sounds as if it is a muffler noise but that was look into and the fire shield was removed but to no avail. could one of the rear struts or shocks was replaced and was no help. could it be the muffler and maybe where the shocks are attached to the frame. i have a 1997 avalon and it has been like this for a long time and no one has helped. thanks for your help.

Answer
Sorry but if the local people can not find the cause I don't think I can from here.
You did not  mention a Toyota dealer, if you have not visited your local dealer you may try that.
Sorry but  noises are tough unless they can be heard or are really common. The Avalon does not have many problems with rear end noises.
Good luck
Jack