O2 sensor
 

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.

Re: O2 sensor
 

Hi lesha30, Welcome. :)

I see 5 questions, not a couple, but I'll let it slide since this is your first time. :laugh:
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. :bigok:
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..