P1133 (02 insufficent switching) bad placement? Cold idle surge?

[PWNED]

When I first got the regal from my buddy he told me that the rear 02 was most likely seized due to the ceramic coated manifold. I went to remove it and out came the threads. I attempted to chase them but it was too far gone. An in expensive alternative was me having a bung welded into the crossover pipe as pictured below. Now it has been 75 miles and this code came up. Weird due to the readiness tests saying the 02 has passed/ran (inspection purposes) this morning. Yesterday and today have been the only times I have actually driven the car as it had a radiator support installed. But I do have a wacky idle concern that happens only on cold start. I will start the car and after maybe 30 seconds the car will surge like crazy and almost stall out but I have helped it in the past (apply gas) in park. It is hard for me to tell is this sensor being in this location causing this as well?

Should I try unplugging it tomorrow morning to see if the problem happens?

Is this a bad spot and triggering this code? I know some headers use the front cylinders for a reading so I just thought it would be ok. Maybe it is spaced too far out? It is a new sensor from GM.

I have attached a tune with some cruising ( when the light came on ) and wot pulls.

[5FDP]

The Powertrain Control Module (PCM) monitors the Heated Oxygen Sensor (HO2S) activity for 90 seconds after closed loop operation has begun. The PCM determines if the front HO2S is functioning properly by counting the number of HO2S-1 Lean/Rich (L/R) and Rich/Lean (R/L) switches.

Thats all it means, it won't hurt fuel mileage nor trip a non ready monitor. GM had a number that they picked, so if it didnt switch enough times within that small time frame it trips the code. Just thinking off the top of my head here, but mabye increase the closed loop from 50º to 80º and see if helps the o2 sensors heat up more.

I used to get that code all the time once my headers were install, but after made 1 month or so it just stopped coming up and I've never seen it again. It would come on maybe 1-2 times per week and that was with a new delco sensor.


Not sure on the idle surge, even though my car has one for whatever reason. Not has bad as what your saying. I'll get 20-30 seconds of idle time then it will surge up and down from 700-1200 rpms for maybe 60-75 seconds then just level out and stop. I even flashed the stock tune back in and still did it, I was thinking its a sensor on the throttle body but in the end I just don't care and it doesnt bother me anymore.

[PWNED]

This morning Before I left for work I did a few cold start scans. The car did not act up at all. Yesterday I did clean the egr so maybe this had something to do with it?

Scan1 (idleno02) I unplugged the 02 before I started the car and half way through I plugged it back in.

Scan2 (Idle) everything was plugged in and I restarted the car. Hit the gas once and still no surge.