I had an o2 sensor go out so I went to my local Auto Zone and all they had in stock was the bosch o2 sensors ( suprise suprise). Now after 3 days I'm getting codes P-133 and P-153 which is slow response. My question is should I return them and try a new set or should I get AC delcos? Is this just a fluke, or are the bosch sensors junk?

 

try a new set......they should have had a 6 month warranty........
but yeah they are junk.......I bought a set and had faults(mine was obd1 though)

 

JUNK.

Get some Delco's. Bosch is notorious for making bad o2 sensors. They are mainly hit or miss.

 

also, in my case, compared with Autozone the GM parts direct delco O2's were about $20 cheaper including shipping.