I know exactly where to start looking
Take out your muffler. Look at all the hose clamps on thaqt side.
There is one right behind the front bare aluminum strut that is hard to tighten (It is right behind the strut). That is one that was very loose from the factory. You will see what I mean when you get in there.
the rest of the clamps need to be tightened as well, but especially the one mentioned above.
Be careful to take off the muffler gasket.
Treat it very gently. Scrape it off with a putty knife very slowly and be careful not to rip it.
I would bet a lot of money that one of those hose clamps are loose......