2001 NISSAN SENTRA 1.8 XE CANADA

I have an ongoing problem of cold start stalling with this vehicle and have replaced several parts including ECM (rebuilt), fuel injectors rebuilt (GB out of California), fuel pressure checks ok. car throws po740 code for trans lockup convertor but trans still runs fine, i presently have po420 and po430 cause cat is out of car (it was melted) and i won't put in new one till i can get it running smoothly so it doesnt melt again ($549), just got po1491 so some problem in evap system now too. Car stalls when outside air temp is low, the lower the temp the worse it stalls, it starts ok at hi, rich idle then hunts down and stalls, it also stalls underway with a/c on sometimes, fuel economy is good, 7L/100km hiway. any advice appreciated as to why it won't hold steady idle when cold, it drops down and then sometimes speeds up.

I forgot to add that the idle air control is new and the tps is new, however i just bolted tps in where old one had been lined up nevertheless i bot a new air flow sensor from a reputable ebay seller, not dealer, and nissan dealer set up maf for me and said it should run fine (it was at 38% or something he said) but he never touched tps, also engine temp sensor is new