locations of oxygen sensors on engine

The V6 has two O2 sensors. The upper one provides feedback to the ECU for fuel trim. It's in the exhaust header between the engine and the cat converter. The second sensor is downstream of the converter and monitors the condition of the converter.

This car is pre1996 no downstream. Just one upstream with a single purple wire going to it.

Have my Cutlass Ciera s 94 put on the machine and the Machine said my O2 sensor was weak is that why when I drive my car it stalls and shuts off at a certain distance and then 20 minutes later it starts right back up and drives for short distance