No idle equipment, and my car starts right up, I do have to blip the throttle in the morning to get the car to start, but it will idle smooth right away. what throttle body are you using, with the 240sx or z31 idle is adjustable, I set mine to 800 and it stays there ok. My startup hg is around -18, goes to 20-1 once I start driving it and alternator kicks on.
I would check for leaks in intake piping and everywhere else, egr wont affect idle, never had one. Never had stock tb so dont know if it could be issue or not, but deleting a lot of the cold start stuff could be an issue to with stock tb, just throwing out stuff here.