I have connected the end of the o2 sensor that screws into the exaust but i cant find the other end that is electrical connection it is a 2000 mercury villager it is bank 1 sensor 2

Possible causes

• Faulty O2 Sensor
• High fuel pressure
• Faulty Mass Air Flow (MAF) Sensor
• O2 Sensor harness is open or shorted
• O2 Sensor circuit poor electrical connection

an exhaust leak would contribute to the problem too. O2 sensors getting wrong readings due to leak which would add more fuel.

Ford Explorer is equipped with two oxygen sensor positioned on the exhaust manifold. Its necessary to replace the oxygen sensor at the first sign of failure. You can get all necessary details about o2 sensor at http://www.wholesalesensors.com/ford-oxygen-sensor/

Mostly with any vehicle, they are mounted on the exhaust manifold, or just below it on the exaust pipes. if it`s a V6-V8, there will be one on each side of the engines exaust pipe before the 2 pipes Y together. Then one before the catalytic converter and one after.

I would take it to a auto parts store and get them to scan your check engine OBD II memory for code errors, before spending money. They should pin pint which Oxygen Sensor it is.

To replace, let vehicle cool down enough for the exaust not to be hot. With the vehicle in park, emergency brake on and wheel blocks. Then you can unhook the negative battery cable, Jack up the vehicle enough to reach the Oxygen sensors, always use jack stands for safety. Then find the Oxygen sensor your going to replace. Unhook the electrical connection and the plastic connection to the frame, then remove the old Oxygen sensor. (New ones will have grey anti-sieze on the threads) Screw in the new Oxygen sensor, don`t over tighten, just snug it up like you would a spark plug, the heat will do the rest. Then hook up your electrical connection and secure it to the frame. Making sure your new oxygen sensor wire is not touching the exaust pipe. Then rehook up your negative battery cable.

Things you need- 7/8inch wrench, penetrating oil to losen stuck oxygen sensors, safety glasses

ones you have your trouble codes, that, will tell you exactly which one is it and youll need to replace the sensor. or maybe your wiring is broken, inspect all your wiring first, there is a special tool to remove the sensor, you need that socket and a ratchet, maybe an extension, and all the o2 sensors are located on the exhaust manifold , before and after the catalytic converter. But first you need to know which one is it, thats the most difficult part.

Bank 1 sensor 1 --- on left side of engine in exaust manifold .
Bank 1 sensor 2----- on exaust system near converter
Bank 2 sensor 1----- on right side of engine in exaust manifold
Bank 2 sensor 2 ----- on exaust manifold near converter

To remove the O2 sensor you will need an O2 sensor socket that you can buy at most auto part stores, or you can dis-connect the wire connector for that O2 sensor, and then slip the wire connector from the O2 sensor through a 7/8 inch box end wrench and then slide the wrench up to the O2 sensor and then remove the O2 sensor. Use plenty of W-D40 to soak the base of the O2 sensor before removing it, and if the wire connector does not fit through the box end of the wrench then cut the wire connector off from the O2 sensor, and you will only need the open end of the wrench to install the O2 sensor, and only tighten the O2 sensor up until you feel the the sealing rings crush down, and do not over-tighten the O2 sensor because they are not supposed to be torqued down.

the 02sensor is screwed into the exaust with wires connected to the engine loom

most cars have only 2 o2 sensors one is below the exaust manifold and the other one near the catalytic converter

One of them is located on the driver's side of the motor and connects to the exaust manifold.

there are several on your vehicle there are generally atleast 3 seperate O2 sensors one on the exaust manifold on the left side( facing the front of vehicle) one on the right exaust manifold( near the firewall on the right side and one on the connection before the catalayic converter. please note that there can also be one after the converter before the muffler as well