Eng light was on.Went to Autozone and had codes read.They gave me a print for the left rearward oxy sensor.Disconnected battery and changed oxygen sensor that caused the light.Now car stalls at every stop. The engine light is off so I flashed with key. It flashes 12 & 52. Car runs great otherwise.I even did 50 restarts and also tried disconnecting the battery again.Lost and confused.Any help appreciated.