My check engine light is on, I have been informed by my mechanic that I need a rear o2 sensor, Bank 1 replaced. I know what sensor I need but I don't how to tell the location of Rear sensor Bank 1, any info in locating this would be helpful. Also has anybody replaced thier o2 sensor? It seems fairly easy after watching a youtube video. This will allow me to save $75-$100 having a mechanic do it. Please Help, Thanks!