Here's the scoop:

My 1998 stick shift Maxima has an intermittent rough idle issue. It starts cold at about 1500RPM, then as it warms up it drops to a rough idle at about 800 and then dips and surges between 1100 and 400, sometimes stalling out entirely. Once it's warm (after about 5 - 10 minutes) its fine, idles at 900 (because I adjusted the idle screw hoping to mask the issue temporarily). No codes have been thrown.

I've checked for vacuum leaks (ye old rubber tube stethoscope trick) cleaned the IACV and TB, replaced plugs, replaced one obviously broken coil pack, replaced the engine coolant temperature sensor (the one that feeds the ECU not the one for the gauge) and replaced the PCV. Cleaning the IACV and TB seemed to work for a couple of weeks, but now it's back at it again.

My theories are as follows, let me know what you think.

A) Pumping brake cleaner through the IACV was a bad call OR it worked for a bit but that sensor just needs replaced.
B) 02 sensors are bad (why no code though?)
C) MAF issue

I've also thought about the EGR and TPS, but the combination of it not having any codes and the fact that it is temperature dependent is leaving me stumped. Please help.