So I've been chasing this rough idle for a month now. Car runs great when driving, but when sitting still and at temp, it struggles to stay above 750rpm. Stalls out when accessories are running.
Have replaced coils, plugs and wires, injectors, throttle body and throttle position sensor, MAF, and cam position sensor.
Anyone have any insight on this?
2003 350z

 

You've already replaced all ignition related items I would have looked at. But one thing that stood out to me is that you mentioned the engine stalls when you turn on accessories (stuff like A/C?). This sounds like you may have a failing alternator or other accessory running off the crank pulley (A/C compressor/clutch, idler pulley(s), or power steering pump). I would pull off the accessory belts and spin each accessory by hand to see how much resistance you encounter. Something might be locking up (bad bearings perhaps) causing the rough idle or stall. This would also make sense since, as you say, when you're driving at higher RPM (more torque), everything seems fine. You can quickly test this theory by simply removing the belts and starting the engine and seeing if you still get a rough idle/stall.

Since you replaced the Throttle Body and Throttle Position Sensor, make sure to execute the .

Hope this helps!
-Icer