How many O2 sensors?

I have a 98 ZR2 with the 4.3.The 8th digit of the VIN is a W.I'm looking for O2 sensors online.Online tells me that I will need 4(2 front & 2 back).I crawled under the truck and I see the 2 up front,but only 1 after the cat.So how many are there,3 or 4? :confused:

3 for all i know, one post cat, and i beleve bank one and two

you have four dude, 3 on your y pipe, and the one right after the cat. you have one on each side of the y-pipe coming off the manifold, one about 1 foot before the cat, and the one right after the cat

you have four dude, 3 on your y pipe, and the one right after the cat. you have one on each side of the y-pipe coming off the manifold, one about 1 foot before the cat, and the one right after the cat
why the hell did they put so many of them on there??? its waistful and more of a pain in our asses isnt it??

why the hell did they put so many of them on there??? its waistful and more of a pain in our asses isnt it??

ODBII compliancy requires 3-4 02 sensors.

you have four dude, 3 on your y pipe, and the one right after the cat. you have one on each side of the y-pipe coming off the manifold, one about 1 foot before the cat, and the one right after the cat
I have seen the 2 after the exhaust manifolds and the one after the cat.I'm going to crawl under it again and look for this one before the cat.

Confirmed,I only have 3.

The one after the cat doesn't need to be replaced, it just monitors cat efficiency.

Confirmed,I only have 3.
thats all i have ever found

Which one is referred to as bank one,that's the one tripping the code.

The one after the cat doesn't need to be replaced, it just monitors cat efficiency.
so your saying i can cut the cat off with no problems?

so your saying i can cut the cat off with no problems?
I would like to know the answer to that question.I've done that in the past to other cars I've had.

No, don't cut out the cat.

Does nothing for performance.

What I meant was that you don't need to replace the replace the post cat O2 sensor. You still leave it in there though.

Bank 1 is driver's side.

No, don't cut out the cat.

Does nothing for performance.

What I meant was that you don't need to replace the replace the post cat O2 sensor. You still leave it in there though.

Bank 1 is driver's side.
Thanks. :smile:

well yes i will get preformence out of it, mine was soooo plugged up b4 i switched to a high flow it was robbing me of all my power and gas mileage, i was just woundern if i would of cut it out, would it have been ok, instead of putting 180 into a highflow cat

Well I went ahead and changed all three.The 2 up front were easy and came right out.The 1 after the cat was a bitch to get out,I had to heat it up cherry and then it came out.I also found out the connector had a tab rotted off.The truck still runs the same.I can't wait to see it the gas milelage is better.

Reset your computer so it can relearn faster.

Reset your computer so it can relearn faster.
Yea I pulled the terminal.

How long do you have to wait to reset the computer when you pull the terminal?I gave it a couple minutes.I came home today and the truck threw a fit.Now I'm getting codes "O2 sensor circuit low voltage"both banks 1 and 2.This truck is going to kill me!!!!!!!!!!

couple minuts should of done it, should have run rough when started, computer has to get its bearings back, but it shouldnt be throwing codes at you, go get them (or do it yoruselfe if you can) ereased

What you are probably seeing is a dirty or defective MAF sensor.

Clean the MAF filaments with TB cleaner and a gentle toothbrush and reinstall.

I cleaned the MAF not long ago but I didn't use a toothbrush.I should've said this before.When I mash the gas,it hesitates and then goes.Then when I would let off it damn near stalls and runs rough for a bit and then evens out.Also forgot to mention after you mash the gas on and off a couple of times,a little smoke puffs when the gas is hit and then after the gas is left off.Does it sound like the MAF?I'm lost and getting pissed off again at this truck.

Hmmm... 2 things to check now that you mention the other stuff... TPS (Throttle position sensor) And your vac lines.

I cleaned the MAF not long ago but I didn't use a toothbrush.I should've said this before.When I mash the gas,it hesitates and then goes.Then when I would let off it damn near stalls and runs rough for a bit and then evens out.Also forgot to mention after you mash the gas on and off a couple of times,a little smoke puffs when the gas is hit and then after the gas is left off.Does it sound like the MAF?I'm lost and getting pissed off again at this truck.

Yip, sounds exactly like a problem I helped a guy on with his truck.

Turns out it was the MAF sensor.

Yip, sounds exactly like a problem I helped a guy on with his truck.

Turns out it was the MAF sensor.
Alright thanks for the quick response.I'll try it this weekend,maybe.If I get the cash. :banghead:

Hmmm... 2 things to check now that you mention the other stuff... TPS (Throttle position sensor) And your vac lines.
I'm going to go over the vac lines once spring gets here or sooner if the MAF doesn't fix it.Thanks .