Bosch O2 Sensor

So this morning my Check Engine light came on. So I drive a little while and it stays on. So I get home and get my scan tool and get the code. It says that the oxygen sensor voltage was too low. And it had two instances of this.

Last winter I had the same problem. Check Engine light would come on in cold to moderate cold weather when first started. It didn't happen all the time but it did start to get more frequent. So I figured the O2 sensor was getting lazy, so I changed it out with a new :disappoin Bosch O2 sensor, problem solved. No more light.

I did come across somewhere where they said don't buy their O2 sensors. Personally I don't think it should be doing this again this quick.:nono: The first winter I had my car the Check engine light never came on. I'm going to see if it happens again. The light is off now. I revved the car up a bit trying to listen for a vaccum leak.

Could it be the O2 sensor again? My gas milege has dropped in the last couple of months. I can't get over 18 or 19mpg now. I was getting about 20 to 22mpg at first.

The code was P0131

How many miles did you drive with this new o2 sensor ?

Around 10-12k. I got it in January or Feburary