I know how to replace the end of the sensor that goes into the exhaust pipe (pre cat) but I cant see where the other end plus into. Do I ave to take off all of the covers or is there an easy access approach?

 

This link may be a good source: http://www.lexls.com/tutorials/EFI/

 

Next time please state year and model of your car, this way its easier for other members to assist you.

Generally you have the sensor with about 10" of wire, and on the end of the wire there's a plug. It's a very easy procedure.