And thank you for taking the time to seach for a topic that already covers your problem rather than starting a new thread!

WOW! This is the SECOND post I've found today that a fellow new member has taken the time to do a search. I think I just might make it my mission on this forum to search for these new, inquisitive members who search and find what they are looking for and thanking each of them personally!

 

My 99 has a bad O2 sensor as well.

I don't have the exact Code with me right now, but I do remember it said...

Heater Circuit Bank 1 Sensor 3.

Which Sensor is this ?

TIA

 

B1S3 will be the post cat sensor.

 

Thank you

 

I had a similar problem with my 2000 Blazer 4wd 4dr. I waited awhile and did extensive reading on the forum. I was decided to go upstream and cleaned the EGR valve hence this can effect O2 readings. It worked for me and gone are the P0171 codes.