I have a 94 accord, ever since I got it , there was a small rattle that happens when i press the gas .

recently the amount of rattleing sound got worse and its now accompanied with a very bad vibration sound.

I checked the tires and had them balanced and rotated but it didnt fix anything.

The rattling occurs with the engine revs ,I checked the exhaust and found that it looks like its coming from inside the catalytic converter - can this be right?

I also noticed that the vibration sound is heavier when turning towards one side - and it has nothing to do with engine revs as its still there if i turn the engine off while running.
I can only hear it over speeds of 35mph or so (not at lower speeds) but it increases as the speed increases almost like something is vibrating with the wind speed.

I did notice a few new rust holes in the muffler but i dont think this is causing the vibration as its still there when the car is running and the engine is off.

any help would be appreciated and thanks in advance.