04 530i strange noise and RPM stutter

[TehPirat3]

Bought the car very cheap with what I thought was only bad O2 sensors. When I bought the car it had lack of power, rough idle and erratic RPMs. I've replaced the MAF sensor, cam and can sensors, and upstream O2 sensors. I also did cataclean, 2 stages of dry gas, and STP injector cleaner. Now the only issues I'm having are rough start and a strange "gargling" sound, I tried recording a video tonight.
https://s.amsu.ng/IdWzMxfp9kUN

Also P0172 and P0175 system rich errors

What should I do next?

[pimpmyride101]

Video doesn't work. Actual rich conditions are rare. I would try checking coolant level and coolant temp because of the gargling sound. If the computer thinks the engine temp is lower than it is it will add fuel and thus rich condition. The gargling sound could possibly be very low coolant level and the temp is inaccurate. It's a long shot because it would have to be really low for that to happen and you would most likely notice coolant dripping. Did you replace the MAF with OEM or aftermarket? These cars really don't like aftermarket sensors especially Dorman.