What is the pop up assembly?
I snaked it yesterday. I encountered some resistance, I think where the slant starts diving down a foot or so before the main soil pipe.
At the 90+ degree bend just before the main soil pipe, I could not get the snake to go any further. After snaking it, I poured water from a pitcher into the pipe, and after the pipe filled up, it was barely moving, just like when the sink was installed. So I think the issue is at that 90+ bend and I need to replace that with smoother bends. I'm thinking PVC and 22.5 degree bends to make it really smooth.
I'm also thinking that, since I encountered some resistance a foot before the 90 bend where the pipe starts diving down, that I could replace that whole run with something that slants at the same rate all the way to the main soil pipe. This would mean removing that sub floor, which I am going to do anyway to insulate and seal because there is tons of cold air coming in. So I could run the new pipe thru a hole in the floor joists by using a hole saw and get the same angle all the way so the water runs faster and has no sharp turns all the way to the main soil pipe.