I bought a 2000 Dodge Grand Caravan since I've replaced the o2 sensor it stalls and idels low if it's too low it dies

hummm ..first add a bottle of ZMAX to 1/2 tank of gas..drive it a day and report back... why worry if its that easy to fix ....

The O2 sensor determines if the engine is too rich or too lean ,, then adjusts the engine to it's optimum setting. If the O2 sensor is faulty you will get a CEL light on your display. An exceptical range of output before an alarm is triggered is about .4 to .6 volts and most OBD will give an exact reading, Why was the O2 sensor replaced?

O2 sensor got replaced because AutoZone told us it needed to be since that's why check engine light came on

The O2 sensor may have been working but was triggered by an actual fault in the catalytic converter (if that;s the one replaced ,,, some cars have 2 ... 1 in the exhaust manifold and 1 at the rear of the catalytic converter)