Car Help

I have a 2001 3.8l Mustang. Just recently I replaced my upstream O2 sensors because the engine was running rich as all get out. Just wondering what would happen if I unplugged one of my 2 O2 sensors. Would the car just run in a open loop?

Open loop with a trouble code, yup.

In reply to Mr_Asa :

Thanks dude, so the ECU does Use both upstream O2 sensors to determine rich/lean mix. Or 1 upstream O2 sensor if the engine has one exhaust pipe? 

In reply to A1aman :

Uses bott upstream.