voltage reading on PO2S:
Readings are off of a apexi turbo timer:
key on : 4.47 (.447 volts) Engine on : 0.01 (.001 volts)
Voltage is tested at ideal and the Engine is at normal operating temperature

Few weeks ago my car started to run very rich and misfired at ideal and leaned out at top end so I pulled it in the garage and started to analyze the situation..
I found out that at ideal, the (greddy)air/fuel gauge was at 8.0 and it should of been at 14.7 at ideal.
so with a little research I figured out that I had to replace my o2 sensor and I did..but after a week of waiting i finally swap out the old oxygen sensor and started the car and ran just fine, but only for a week. Now it is doing the same problem again misfiring running rich as hell at ideal, and leaning out at top end
o2 sensors aren’t cheap!!
I want to know what is causing my 02 sensor voltage to drop and could it be my IAC valve?? Wiring ?? injectors??

Mods that i have that can effect the o2 sensor parameter:
OBD 2 with Vafc and Greddy blue box
Str intake manifold
Straight pipe 2.5
FPR set at 4 bar (57.2psi) 310 cc injectors (running stock boost)

 

??