I am having issues replacing/finding the bank 1 o2 sensor. Common sense tells me its before the cc...but I can't see it any idea would be great. It is a 2002 monte carlo i believe the 3.8 motor. Any help would be great. Thanks

 

Pretty sure if its the 3800, its at the end of the rear exhaust manifold right before the flange.

 

 

I just replaced mine. You have two, one is between the firewall and engine. Remove the bolts in front dogbones and rock engine forward. The other one is underneath middle maybe a tad toward the front. Its on top on the exhaust between the floor and exhaust. Not hard at all. Hope this helps.

 

i recently pulled the cat off a 2000 SS and the upstream O2 was right there on manifold as pictured above. Let me tell you this though..... it was a ****** #$%^&* to get the O2 sensor out of the exhaust pipe while I had it totally off the car and Very easy access. I could only imagine trying to do it behind the motor........ BTW I ruined the threads taking old one out. hac to buy a new one to put in the new cat pipe.

 

An O2 sensor socket is a GREAT thing. It's a little extra deep, and is open on one side for the wiring. Expensive, but I can't imagine taking the top sensor out without it.

 

I second the O2 sensor socket, I have no regrets about owning mine. And it's not like I change O2 sensors everyday.

 

Yes, get a oxygen sensor socket. Makes the top new a piece of cake. On the bottom one I just used a 4-way angled wrench and had no trouble at all. Always the right tool for the job makes it easier.

 

Ok can someone help me. I have a 3.8 monte carlo with 270xxx miles on it and my check engine light is on. so i when to auto zone and had it scanned. I get 2 PO134 codes a PO131 and a PO141. I changed the rear 02 senor just about a year ago and the front 1 about a month ago can someone help me I don't know Wats going on.I ordered both parts off of ebay😧 but the rear one has held up until now