X5 4.8i 2008 E70 - DTC Codes Help!!

[Beto66]

Greetings everyone,

I need help with the DTC codes for X5 4.8i 2008 E70:

P0056- Oxygen sensors 2/2 circuit?
P0305- Cylinder 5 misfire
P1330- Manufacturer specific?

When idling, car is not running smooth which confirms the #5 misfire. Not sure if there is a way of checking whether the O2 sensor(s) work (bank 2, sensor 2) and that would be causing the misfire?

A knocking noise is also present, mostly after it had a chance to warm up (when starting cold, is very low in the background). Would this be the third code (P1330)?

In advance, I appreciate the help.

Beto66