Check engine code P0430

I have a code of p0430 catalyst converter. My car has a loss of power and recently started making a knocking sound I think from inside the engine. When I step on the gas it gets a bit louder. Also, when I let go of my brake my car kind of bounces or jumps I guess you could say. I took it in and the mechanic said it was my camshaft sensor and my crankshaft sensor. So I replaced them and my car still does the same thing. Can you please give me a few suggestions of what might be going on? Thank you