HELP ka24de, misfiring, running rich/black smoke

[hoopD240]

i am close to taking this thing to nissan, i bought the car running like this, i have changed plugs, wires, 02 sensor, and the aiv is removed and plugged, the car runs fine until about 3k rpms(smokes all the time though), but than it starts misfiring and smoking even more, i am not getting any CEL light, and car still has all the power, and the smell of exhaust is really rich, need help please!!

[greencar]

Have you checked the engine temp sensor, if it is bad/ not reading, it will cause this, you have two ect gauges on you car, one for the gauge cluster, and one for fuel trim. hope this helps.

-Dan

[hoopD240]

is there any way to check if its bad?