Revolutionize Fuel Economy Bank 1 Sensor 1 O2 Sensor and Its Impact

Im debating if its the O2 sensors or the exhaust? Is there anyway to really tell? Any help would be appreciated. Thanks! I've been searching google and I am confused as to which one this actually is and what part I need to get. I am not sure if it is upstream or downstream, front ... Which o2 sensor is one and which one is two? If I'm right bank two would be driver side and sensor one would be the front or before the cat. A properly functioning oxygen sensor will show a rapidly fluctuating output voltage between approximately 0.1 and 1.0 volts. However, it is not very specific as to whether this is bank 1 or bank 2, and given that these are pretty expensive for the pre-cat sensors, would rather only ... I used a pair of long needle nose pliers to hold the plug from above and then I used a small flathead screwdriver to press the tab and separate it the plug. I'm working to replace all (4) O2 sensors on my 2006 EX-LT after getting code P0154 for Bank 2 Sensor 1 (155k miles, prob originals). On a V configuration engine, the front most cylinder is always number 1. And the bank with no. 1 cyl. is Bank 1. I have a 2012 Ford Focus SEL and there's a code (P0131) O2 sensor circuit low voltage bank 1 sensor 1. I replaced the O2 sensor (Bank 1 Sensor 1) assuming it ... A "code for the O2 sensors" does not mean that the sensors are bad. The sensors are simply reporting that a condition outside the parameters of the sensor is ...