So I need to replace the socket side (female) that runs to the ECU. I can't find a replacement part anywhere. Maybe a Junkyard. Anyone know where I can get one?

 

Yes, junkyard or try searching CL / FB marketplace for a local guy parting out their car.
I did this with the connector to the front blinker on my R53.
Hot tip, you do not have to splice the wires. You can actually slide the pins out of the old connector and into the new one. It’s a little tricky, you have to be careful but it’s likely to be more reliable this way.

 

Nod, Yah I think I have to visit the local yards. I tried to move the pins cause I might be able to resolve the weak connection but I couldn't figure out how to release them.Usually you insert a screwdriver somewhere and I unlocks the pin.

 

Um, seems ironic NAM member oxygenmini needs an O2 sensor connector...

 

I looked up the part number for the connector housing for the downstream O2 sensor. Ordered 5 so I can make up my own replacement. it's amazing what you can dig up with a search.