Hi, guys...

I have a couple of questions about the 02 sensor for my 91 4Runner V6 2WD, auto 97K :

1) how often do I have to change it?
2) how many O2 sensors there are?
3) How much do they go for?
4) How do I know if the sensor is bad?
5) What affect does a bad O2 sensor have on the truck?

Thanks

 

I'm gonna stick my nose in on this one and ask about answers for #1,2,3 on a 3rd gen please.

 

Hi lesha30, Welcome.

I see 5 questions, not a couple, but I'll let it slide since this is your first time.
It's recommended to replace them every 50K miles or so.
On your truck, there is only one. It's right in front of the catalytic converter. To piggy-back this on for the 1997, there are 2, one in front and one behind the cat.
About $100.
Poor fuel economy and/or power from the engine. Failing or really high emissions.
See answer #4.

You're welcome! Glad to have you here.
Galen

 

You can also check the sensor with a more advanced scanner.
If the voltage is out of range (or close to it) then replace it.

 

umm, i think mine has 2. 1 before the catalytic and 1 after.

yep, just checked. the 1 after the CC is actually mounted on the pipe in just in front of the muffler.

must be a CA emissions thing.

 

Yes it is. i have heard that before..