My Service Engine Soon light has been coming on for the past month and everytime I have it read out it shows a O2 sensor is at fault. So far I have changed 2 out of the 3 sensors, the one in line with the exhaust and the other on the right side of the exhaust downstream, after changing these two sensors, today the light came on again. Once again I had the code read out and it shows the O2 sensor again. Could it be the sensor on the left side downstream? Any help would be welcomed.

 

You have to post the codes from the scanner or we can't help properly.

 

The only info I could get was, "Bank 2 catylst below efficiency", if it pops again I'll retain a copy of the print out when I get it reset again. I probably should go ahead and change the other sensor.

 

Could also be that your cat is dying??

 

Really? You have all your stock cats on her? Those rear O2's hardly ever fail - infact I haven't seen one fail yet. - Check the rear CAT drivers side for leaks under the heat shield. Liston for it leaking . Check your harness back there by the O2 sensor..

Sounds kinduh goofy - Auto Zone scans codes for free - I hate giving advice without the numbers..

What engine do you have , how many miles?

 

I have the 4.2 with 89,700 miles on her.