Hi,
My smog test was borderline this time, NO was high, and I was told maybe the oxygen sensor could be changed.
my 96 4Runner v6 has about 93K miles on it,
I don't think the O2 sensor has ever been changed...

Any ideas on how to change it? (instructions anywhere?) and how often should these be changed?

THANKS

 

Hope I can help. Any repair manuel should have location and how to change. As far as enterval I;ved read manufactures now reccomend 60-70K. They also say this helps keep milage up.

 

You should do a search first, I'm sure you'll find what you need if you look. Ok I'll be nice and give you a good start: http://www.4x4wire.com/toyota/4Runner/tech/O2_Sensor/

Also, when was the last time you did a basic tune up? Clean your MAF, change plugs and wires, maybe some fuel system cleaner, clean your throttle body... You change your O2 sensor when it goes bad. Some go before others and theres not really a typical mileage that they go out. Though, since yours probably has never been changed, it could be suspect. There are people with well over 100k on there O2 sensors and they still work fine though. Maybe its a bad catalytic converter?

I'd recommend just doing a good tune up and cleaning things up before replacing the sensor.

 

There is no real set time you need to replace the sensor but when emissions begin to go south that is a pretty good indicator that you might want to look at changing it. High NOx is an indicator that either you are beginning to run lean or that the converter efficiency is going down. Since the O2 sensor is fairly cheap, that would be a good start (only use OEM sensors from a dealer or URD . Then have it retested to see if you are back within spec. If you still have high NOx then the converter would be suspect.

 

Bump.

My 4runner 3.4 had 314k until new cat was put on, then I passed smog but now2 months after I get cel code po172. Maybe bad or dirty MAF?