First things first: What year and model car do you have?locosteelersfan said:I get this nearly all the time since last week, but twice I got P0101
(maf sensor) which I'm ignoring for now. So what just buy the O2 sensor or
is there another fix?
The O2 sensor is probably the problem, though you may also have a MAF problem as well. The B2S1 sensor is the one on the front bank of cylinders. Some people have had good luck by cleaning off the O2 sensor head with an air blast and/or some yet unknown O2-sensor-safe solvent. Those techniques have unfortunately not worked for me. If I was you, I think I'd replace that sensor with a Delco one rather than a Bosch, clear out the codes, and see if the MAF code comes back. You can order the sensors for decent prices from several sites online including www.gmpartsdirect.com and www.rockauto.com. Let us know what you do and how it works out or if you have any questions or problems...