Weird sound under intake manifold - and misfire

[F1WANNAB]

Hi. I hoep someone can help understanding what is going on with my 2010 523i with the n53 engine.

It suffers from misfire on cylinder 2 according to my tester. I have recently replaced the NOx sensor and the fuel pressure diffential sensor. The car has done 111.000 km. Lately I have occasionally felt a few, what felt like, misfires while driving at speeds between 60 og 100 km/h. Yesterday morning the engine was running very rought and after 30 or so seconds displayed check engine and "drive train error".

My tester pulled the folowing codes:
150202: Ignition cylinder 2: Combustion duration too short
140201: Misfire cylinder 2: Injection is cut out

I have replaced the spark plug and coil on cylinder 2 and this did not change anything. The old plug was fine, grey, no fuel or anything.
The engine is also making a strange noise when idling. It gets louder after it has warmed up. Its a raspy, quite loud, noise and seems to follow the revolution of the engine, when it struggles to keep running. It i like "Scratch scratch.... scratch scrath.....scratch scratch" It comes from somewhere under intake manifold or airbox. i think near the throttle body, but i'm not sure.

I have bought a new injector to try out but is hesitant to open the package before understanding whether this is a fuel related problem, since I have this strange, apparently "air related" noise.

What could be generating those codes?
Br Troels/Denmark

[DontTouchMyRide]

My E46/M54 also suddenly developed rough performance and hard starting, with P1349 code..Misfire cylinder 4. I moved the spark plug to cylinder 2 and the coil to cylinder 1 but still get this cylinder 4 error code?
If I stop the car and turn the engine off for a couple of minutes then resume my journey it may clear completely or keep recurring every so many minutes???
The only other thing particular to one cylinder is the injector, so I am also at the same point....unless it's a valve, but just one cylinder?

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BTW, I'm currently in Ethiopia so I can't just keep throwing pots at the problem so if anybody out there can shed some light on our problem I for one would be eternally grateful

[JJ22]

From dealing with some of the same issues I have learned that when a injector leaks and that cylinder runs rich the ECU starts to lean out other injectors to compensate and the cylinder that runs lean is the one that throws a code. My suggestion is pull all spark plugs and examine then take it from there.