The Nissan Path

It was running rough at idle for quite some time but this week it started getting brutal and stalling sometimes. However over 2000 rpm it runs really smooth, so I don't think it's fuel or spark related - maybe I'm wrong. It's thrown codes P0171, P0400, P1400, P0325 so far. I removed and checked the vacuum and EGR function, all seems fine. The solenoid clicks too. It looks like a vacuum leak according to the live OBD2 scanner, the short and long-term fuel trims are +5-20%. Also the spark advance seems to be from +5-45, all over the place. I have recently replaced the MAF, fuel pump, cap, rotor, plugs, wires. All the vacuum hoses seem fine and after removing each and plugging the line to see how it affected idle, they all did nothing. I'm thinking maybe the distributor or O2 sensors are wonky.....any help is much appreciated!

Have you check the hoses of the vacuum that are located on the right hand side of the engine, these are two hoses that come from the back of the engine to the front, I had it once cross over connected in which gave me the EGR recirculating, there is a hose also all the way in the back if I remember by cylinder #6

Since you have an obd2 reader, what's your maf reading at idle and under load ? also, what is your pre-cat o2 voltage look like ? does it oscillate or stays pretty linear ?