RaptorZ28

I didn't want to hijack someone else's thread, so I started my own here....

These O2 Sensors are a big pain in the A$$, I just replaced bank1 sensor 2 and bank2 sensor 2 Friday and then Saturday the SES light went back on...I've replaced all four at certain points.

I've done 0 upgrade work to the engine...I don't mean to hijack your thread, but can anyone explain what the deal is with these things? is this common?

I am now wondering if its' the computer even though i'm gettin bad O2 codes. It's a '99 Z28

2001NBMZ28

Welcome to the board. What code(s) is it throwing? After cat codes just monitor the cats.

Z28luvr

If your car has less than 120k, GM will replace the cats under warranty ...if in fact the cats are the issue...might be worth looking into.

RaptorZ28

Thanks for the response....unfortunately the cats are warrantied only up to 80k according to the dealer by me. If you know otherwise please let me know...but they did hint too that O2 error codes can come up and it is really the cats.....

Thanks for cluein me into this cuz I was at my wits end with these sensors and replaceing them now there's at least something else to look into.

2001NBMZ28

Your dealer is correct - the 10yr/120K extended cat warranty is only for the 00-02 cars.

RaptorZ28

Update, after much working, and finally breaking down and taking the car to a dealer, the problem has been resolved....albeit I dropped 150.00 and they fixed issues that wasn't part of the problem to figure it out.

Apparently, the first reading on the computer was Bank1 Sensor2 Bank2 Sensor2 were bad. So I replaced em. Next was that Bank1Sensor2 Bank2Sensor2 voltage was low....(this is where the mechanic fixed some stuff that really wasn't the issue but w/e)

I drove a mile after he did that the check engine light went on again....took it back to the dealer right away hooked it up to the computer again, and it read both rear sensor's bad again...

Some of you may know this already, but I didn't and the mechanic actually saw some S10's where this happened, but we unhooked the MAF Sensor connection and ran on back up.

It worked.....the car was no longer running lean at 3000 rpm or around the 30-40 mph speed, which was typically what kicked off the Check engine soon light after clearing it. But the bothersome thing about this is that the computer never read MAFS was the problem it always pointed to the O2's....

Well, I hope this in some way helps someone out there...but after replacing the MAF Sensor things seem to run like the car I once remembered a year and a half ago...too bad it's almost time to get an '09 ; )

Some confusing points was why was it running lean on O2 sensor's 2 and not 1 if it were the MAFS but again as I say just in case someone runs into this issue....maybe this'll help ya out