I know it's not an F-body, but I need to help my neighbor out.

If the right rear O2 sensor is disconnected (The 95 vette has three O2's, the third is on the right side behind the CAT) will it prevent the PCM from going into closed loop?

If so, is there a resistor that can be plugged into the harness to fool the PCM as I have seen for OBDII cars?

 

It probably would prevent the car from going into closed loop. I dunno what resistor youd use but O2 sims that work on Fbods should work on Vettes too.