Noise under 4Runner

hey wassup ya'll i have a 95 4Runner and i just drove from my parents house in San Francisco back to Las Vegas and i just noticed when i was sitting at the light. a loud rattling type noise coming from under my 4Runner only when its in drive its pretty loud anyone got any suggestions on what it is or what i should take a look at when im under it?

Check your cat converter/exhaust heat shield for looseness. Tighten if possible.