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Is the knocking loud when you start it? It sounds like a bad bearing and the oil pump may have failed.. Can you check the codes in the PCM and also perform a manual oil pressure test when cranking and let me know what it has?
Can you take a recording and attach it so I can hear it? It's most likely a bad bearing and you will need an engine..
If the knocking is coming from the engine then that isn't good, and the P0300 saying all of the cylinders are misfiring. The only thing that you can do is drop the oil pan and inspect for metal..