How to Replace the O2 Sensor in Mercury villager?

O2 sensor needs to be replaced when you get low gas mileage in car.
The procedure to replace is as follows: ----
1) There is primary and secondary O2 sensor connector.
2) Do the replacement of the O2 sensor only when the engine is completely cool.
3)You will see primary O2 sensor on the exhaust manifold.The secondary O2 sensor is located after the catalytic converter.
4)Put the car on jack stands on the rack, this will give you proper sensor location in the car.
5)Remove the O2 sensor with a socket wrench and O2 removal tool extension. Turn the O2 sensor counterclockwise to remove.
6) Most of the times the O2 sensor comes out very easily but if its bit hard to remove it then you can use "FREEZE spray" to make it gets loose.
7)The spray will make it come out easily.
8)When the O2 sensor is getting removed, some of the wiring's will also come out.
9)Before removing the O2 sensor, take the note of the wiring's and the position of wiring so while inserting new O2 sensor you don't get confused.
10) Now after you remove the old faulty O2 sensor out. Carefully insert new O2 sensor in same position.
11) And reverse/refit all the wires / parts which you removed while replacing the old O2 sensor.
This will help. Thanks.