E36 M44B19 multiple random cylinder misfire

Hi. I am recently getting p0300, p0301, p0302, p0303, p0304 using an OBD tool. I have replaced coil pack, sparks plugs, camshaft position sensor, valve cover o-rings, fuel filter. The strange thing is a I getting only p030x codes and nothing else. I have been thinking about fuel issues like low fuel pressure and I wanted to measure the pressure but isn't a fuel issue supposed to bring up another obd code? My compression seems fine and plug wires are the only things left regarding the ignition. I have poured one liter of 10w oil in the gas tank while being full of gas in order to clean up my fuel pump in case of malfunction.

What do you think? Any ideas?

Notes:
1. Idle is not at the same point every time when the car's wheels are moving.
2. When I make a pull, usually in third gear in the highway, at about 5.5k rpm it sounds like its hitting a light rev limiter but it doesn't feel like so. It definitely doesn't hit the limiter.
3. When idling parked, its a little bit shaky.
4. In the past, I found a cracked breather hose causing a vacuum leak and replaced it.

Thanks in advance. :)