I'm trying to help a friend with her 2006 Taurus with a 3.0L V6. The check engine was on and it was running really rough. I took it to the parts store and got the following codes: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P2195 and P02196. Seeing the two codes about the O2 sensor for Bank 1 Sensor 1, I bought a new one and put it in. I was told that the Bank 1 sensor was the one near the firewall so that's the one I replaced. I cleared the codes before running the car with the new sensor. The car initially ran smoother but after a few miles, the really rough running came back. I went back to the parts store and now I got the following codes: P0300, P0301, P0302, P0303 and P2196. I'm thoroughly confused. Anybody have any ideas? Thanks.