I'm ready to install an O2 sensor (rear) on my 95 SE. TwoQuestions:

The Haynes manual describes a special tool to remove the old sensor. Is that necessary? Is the sensor that difficult to remove?

I also need to replace the knock sensor. Both the rear O2 and knock sensors were checked by Nissan and they are both bad according to them. Will replacing only one of them right now damage the other?

thanks

 

The O2 sensor and the knock sensor aren't actually related to one another.

To answer your questions: yes, you need the O2 sensor tool. No, it's not hard to do. No, you dont have to replace the O2 and knock sensor at the same time.

 

Haynes (page 6-15) says "Using a suitable wrench or special oxygen sensor socket, unscrew the sensor ..." On many cars the Oxygen Sensor may be removed with ordinary hand tools. Accessibility varies by model year and whether the engine has the California emissions equipment. The special Oxygen Sensor socket is available from several sources. The least expensive one is Harbor Freight #36669, $5 + S/H. http://www.harborfreight.com/cpi/cta...emnumber=36669

The Oxygen Sensors are screwed in tightly. If you have difficulty removing it try running the engine for two minutes, long enough to make the exhaust system warm but not hot. A liquid penetrant may help.

The Oxygen Sensor and Knock Sensor may be replaced individually without harming the other one. I suggest you replace the Oxygen Sensor first. There is a chance that the new Oxygen Sensors will "clear" both Diagnostic Trouble Codes.