Hey guys couple questions

[vg30de93]

I have a couple questions tonight for yall. First has to deal with the Nissan Datascan. It has a data display feature that some of you may be aware of. And in the data display it reads the O2 sensors. However it doesnt show both at the same time. I have heard that by unpluging one you can read the other one. So i tried this theory. The ready was normal going back and forth between rich and lean, but when i unplugged the drivers side, the passenger side O2 signal reads 31/32 Lean and just holds no matter what. This seems very odd. And when i connect the drivers O2 back up, the reading shows rich, then begins to go back to normal. But if i unplug the passenger O2, there is no change in the drivers reading. I have doen this one 3 cars in the past couple weeks all showing the same thing. One has brand new O2 sensors (less than 5k). So what do yall believe is going on. Also no codes are being thrown. (1st 91 Slicktop TT, 2nd 90 N/A, 3rd 91 slicktop n/a)

The last question has to deal with the IAC. I had set the 91/ n/a TPS to .46-.48 V. I then unplugged thge yellow connector that goes to the IAC. i thin adjusted the throttle down to 750-800. AT 750 nissan datascan shows his timming at 18-19 degrees. I havent had a chance to get a timing light on it yet. But when the IAC is reconnected the idle shoots up to 1500-1700. And the IAC does not cut off when the car reaches operating temp. What should i go about check with the IAC. also no codea

Thanks in advance guys