Thanks again. Bringing car to shop later this week. Will let you know the story. Thanks again

So yesterday muffler shop found a small leak at the flange of the DRIVER's side downstream catalytic converter. He put some muffler epoxy to the flange and that stopped the leak. He checked the connections on the PASSENGER side downstream O2 sensor and then erased the codes. As of last night 5 of 7 IM readiness monitors reported OK for "this drive cycle" and "since codes erased". Waiting for drive cycle to report on the 2 remaining IM monitors the O2 and the Converter. Took it to two other shops and both said that if it gets the PO137 code again that I should replace the O2 sensor again as maybe i received a defective sensor. One other thing is driving me nuts is that confused which bank is bank 1 and which bank is bank 2 No drawings for this 2007 IS350 is killing me. Thanks for the support. I should know more when son-in-law comes home from work and I can scan it again to see if all IM readiness monitors have reported OK. Thanks again

Ok. So here is the latest. Son-in-law took took vehicle yesterdayto the emissions station and it passed. While he was at work and based on what theshops had told me about possibly receiving a bad O2 sensor, I bought another one. Didnt open the box but just had it. In case theP0137 came back again. Well the son-in-law texted me late yesterday. Evening that it had passed the tests. So I'm going to hang on to this new sensor for a few more days and then if all is still good return it for a refund.

On another note has anyone ever toyed with the idea of an oil catcher to collect oil blowby in the manifold. Supposedly this helps to keep the valves clean as a GDI engine doesn't spray the gasoline above the valves which helps clean them. Just curious. Thanks all for your kind help. Hoping this MIL lamps stays off for another year. Thanks

I bought the sensor from Advance Auto for $113 plus tax. Total $125.28 (Illinois and Cook county is high tax). It is a Denso sensor. It was the closest place that had a Denso (I believe they are the OEM for Toyota/Lexus). I didnt want to buy a Bosch. And the local Toyota dealer wouldnt sell me one because it is a Lexus even though Toyota and Denso are stamped on the part and Lexus wanted $210 for the sensor.
The muffler shop is a place called Fair Muffler. They've been in business since the 50's. Family run. The guy there said the leak was small and the epoxy should take care of it. He also traced the wires from the sensor to the connector and made sure the connections were snug and good. I've learned that you have to dig and dig for information and this forum is a great help. Hope this helps.