Every time I hit a pot hole or good sized bymp, I hear a rattle vibration sound from under the driver side. Doesn't sound metallic, but I'm not sure.
Might be a loose heat shield that is attached to the catalytic convertor. They tend to rust and come loose. Find a muffler shop or your local mechanic to reattach it. Do let them sell you a new exhaust if that's what it is. it can be tack welded back on for a small price
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