Hello, does the vehicle restart when stalling? What does it take to run the car again?
An electrical issue consisting of or resulting in low battery voltage would not restart until the battery is recharged. However, if the vehicle starts again, you're not looking at electrical -- you're looking at engine performance.
Once you know how to go, then testing has to performed in the correct relative area.
A "machine" from AutoZone means and does absolutely nothing to benefit you.
A "machine" cannot tell you an O2 sensor is bad. Or anything else. If it did, we wouldn't need to send technicians to school to learn about how to diagnose and repair vehicles and invest in costly diagnostic tools to help diagnose and resolve concerns.
What it sounds like is a short detected in the circuit of an oxygen sensor, an open circuit pertaining to an oxygen sensor (by the way -- there are 2 sensors -- so which one? Upstream? Downstream?), or a fuel trim issue related to ineffective oxygen sensor readings -- which can be caused by multiple factors. As a note - a fuel trim issue where it leads to the engine getting flooded with fuel - or starved of fuel - will most certainly cause an engine stall at some point in extreme cases.
Additionally, it is highly likely that no one at AutoZone is trained, skilled or educated enough to tell you what an oxygen sensor will or will not do, and as a result should not be passing judgement on it's effect on your concern.
You'll need hands on diagnostic testing by a skilled professional with proper tools, equipment and reference materials.
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