I have a 2001 is 300 and check engine light came on so I took it to meineke and they said it was pre cat sensors, but that I should replace all 4, they wanted $700-800. So i went online and got universal o2 sensors for around $40 a piece and installed them my self. now I went to orielys to get them to clear the code and i am still getting po161 which they say is bank 2 sensor 2. now there might be a small exhaust leak where the down pipe and mid pipe meet. could that be what is throwing it off? and also the o2 sensors i got required me to reuse the wire harness which means i had to splice them together w/ butt conectors. is this a good idea?,