Yet again something is wrong, after every bumb there is a rattle or something is loose by the front left a pillar ( right under the dash board) but when I try to hit the dash on top to hear the noise I get nothing, so it's only on bumps, possibilities ???

I took off the cluster and I see nothing except the venting tubes for the heat and a/c

for me it was my coins that was in that little hidden flip down compartment. i had it literally stacked with quarters and i guess the weight of it made something rattle. i put the coins in my ash tray now since im not a smoker cause the rattle annoyed me.

Nope its not the coins, I dont have any in there

I have a similar situation w mine ride too. A buzzing sound everytime i only start the car. It lasted for abt 10-15 seconds then stop. Cant figiured out what it is either.

The sound you are hearing is the brake booster. If you have your car running in park and you pump the brakes a few times you should hear the noise come on.
Thats just how this GS works and is not anything to worry about.

It never use to do that before til recently .