hwalker

My 03' 350z has been great until recently. All of a sudden one day when I went to start my car I noticed the engine was turning over pretty slowly, so I ignored until it just kept getting longer and longer and I realised I need to get this checked out. So I had some codes ran and I got this P0327 knock senor circuit low input (bank 1)------PO340 Camshaft position sensor circuit (it gave me this one twice on the same reading for some reason). I'm not sure what I should do after this. I read online that there are no "bad knock sensor" so like you would need to replace it codes, but I don't really know how to interpret this. If you do know could you enlighten me and give me an estimate on cost if you can?