Would a bad O2 sensor cause stalls?

I received codes indicating that an O2 sensor is bad with conditions being too lean for bank 1. When i unplugged the O2 sensor and started up the car no lights came on. When i slow down or brake the car sometimes stalls. I was reccommended that it might be a vacuum line that was bad, but if that was the case it would be stalling out all the time and would be hard to start back up, and since it only stalls every couple of days maybe it's just a bad sensor. Can O2 sensors cause stalls? Car doesn't shake or dog around the engine just turns off, and i restart it with no problems.

Would a bad O2 sensor cause stalls? No, but it isn't helping.

How many miles are on the car?

What is the year and engine size of your car? I'd replace the o2 sensor if for no other reason that it is a wear out component and since you have a code on it you ought to go ahead and change it out. First things first. Then, if it still stalls out be looking for a vacuum leak or a bad IAC valve. Have you ever changed the plugs and wires? How about the air filter element? PCV valve?