Why is exhaust vibrating on a 94 Honda accord lx?

Answer 1

look underneath your car from muffler back and follow the exhaust pipes. Look for any loose/broken/rusted clamps that keep your exhaust pipes connected to the heat shield (metal strip surrounding exhaust pipes to prevent damage to car under body or anything underneath. It may be separated at a part so that when you rev your engine or at least turn it on the shield hits the pipe causing the vibration/noise. If not then look for anything else hanging or out of the ordinary or have someone else look at it.