Whenever I press on the gas regardless of my speed, a loud rattling sound comes from under the car, usually happens after I make a stop and start to take off again, I just replaced muffler and that didn't make a difference.
What is causing rattling noise coming from underneath car when I press on gas? on 1994 Honda Accord
There ma be a loose heat shield or a broken hanger. When the exhaust is cool try banging on it in different spots with the palm of your hand.
I agree with chevy power but it could also be a catalytic converter
def in exh system somewhere seek est from muffler shop
Check converter heat shields , they rot out and get loose. Your description of symptom fits that perfectly and is quite common.