Hello, everyone. I've been working a lot on a Sable that we've had for about 8 years now. It's been all right with few repairs until the past year, when we needed a new transmission and a ton of other stuff, and it's still not fixed. I think we're getting close, but I'm not sure. In the GM 3800 community, there's a little chip that plugs into the rear O2 sensor to tell the PCM the cat is performing optimally when one may have a "high flow" cat or none at all. My Sable had both of its cats totally clog up, so we cut them out. That's so much cheaper than the delaer's $800 cost or some local shop's $600 estimate.

I'd like another cat, but I really don't understand why I need to have one per 1.5L of displacement. There's a Magnaflow high flow standing by, ready to replace the resonator. This model, the 94006, has been used by the GM 3800 community to replace the stock catalytic converter, and it's extremely efficient without setting off engine codes. Whichever route I choose to take, no cat or Magnaflow, I'd like to wipe out the rear O2 sensors. Can I hook up a tuner and erase the codes as I've seen done with many GM 3800s, or is there possibly something that plugs into the O2 sensor's connector and acts as a proper sensor?

Without the cats and with functional rear O2s, the car has a constant SES light. It also sounds really throaty at idle and raspy at revs. I made a couple videos and posted them to YouTube:
http://www.youtube.com/watch?v=Si7rNXr2Z8w
http://www.youtube.com/watch?v=mmalNYP1BqQ

Thanks a lot!