No, I havent done any of those things. As for the code being for upstream or down, I dont know that either but I bought the upstream sensor today from NAPA, 81 bucks. From what I've read online though, it is most likely the upstream and if not, at least the downstream one is supposed to a good bit less expensive and easier to replace. I am no longer able to crawl around under cars so I am going to have to pay a man to replace this one for me, maybe the downstream one I can do myself.was the code you pulled for the upstream,downstream or both 02 sensors? cod also have a melted down cat . a vacuum snap test would verify if or if not . if you disconnect the problematic o2 sensor with it running does it smooth out ? have you checked voltage outputs from the sensor or input voltage ( if it's a heated type ) ? those things arnt cheap just to be guessing .