i have a 2000 blazer 4x4 4 door 4.3l and i got it like 3 or 4 months ago and when i was test driving it the check engin lite came on the dealer i got it from took it to a shop where they did a tume up and changed the o2 sensor yesterday i saarted having really bad trans problems (unrelated) but at auto zone there scan came up and said in addition to the trans codes i need an o2 sensor. im wondering if theres something causing the 02 code or my o2s to just crap out. any thoughts would be appreciated

 

Kind of need to know the codes as that will pin point which O2 sensor(s) is/are throwing the code(s).

 

Generally the 02 sensors dont just die, smae with the cat. Check your fuel pressure, and more importantly look inside the upper intake, if its clean you ahve a leaking spider injector hose.

your tranny problems could be related to engine problems and might go away once the engine is fixed.

If your not a DIY, this is one area best left to the pros, take it in and have the dealer do a diagnostic test on the truck. It might cost $80-$100. But you will save that by not replaceing a bunch of parts for no reason, especially the tranny.

If you want to do the work yourself, let us know.