Thanks for the help and suggestions guys.

Just figured I would post a fix in case anyone else comes across it in the future. It was indeed the pcm. Got a replacement one in and programmed and now both o2s are reading and flucutating nicely.

Now since I decided to go wot on it during the test ...

No this is the upstream o2 on the rear manifold. The rear o2 sensor mv are switching slightly when monitoring with scanner. the front o2 is a steady .450-.445mv which is just a reference signal sent from the pcm.

yea i did check the ohm reading of both signal purple and tan wires back to the pcm. It read .3-.4 ohm. According to GM spec anything under 5 ohm is good..but 5 ohm seems kinda high.

I did verify it has power and ground at the connector pins on the pcm side. I have not left it plugged in and back probed to make sure its getting to the o2 sensor yet. However all the pins look good and not bent or loose or anything.

Yea I did get the correct sensor for the year the 94-96 have the old flat style connector and the late 96 up have the "cube" type connector. I checked and I have good power and ground through the connector, however through the trouble tree diag I did get some varances in readings and traced wires to ...

thanks for the welcome and fast replies guys. As for the brand I have no idea, I know its not a bosch or delco, probably some cheape chinese one.

I actually replaced the battery the same time the o2 sensor was changed out as well so it should have cleared the memory as well.

Hey guys, newbie to the forums here but not to cars.

I just bought my 96 SE for $700 with a dead #1 rod. I have since replaced the engine with a 98 Bonny. Everything went nice and smoothly and engine runs great. However I had a code pop up orginally as a p0133 for o2 sensor slow response. So I ...