Down on power

[bmwlover0725]

This damn car...

So in trying to diagnose an unrelated issue, I came across another potential problem. I am running turner's catless pipes, but this has been an issue since the vehicle had cats and I never looked into it. Today I accidentally picked my downstream instead of upstream sensors to monitor and noticed a strange pattern. I revved it to about 2k and the switching for bank 1 seemed off. I've added a photo from my scanner that I took during this whole thing. I know these sensors don't do anything for the car seeing how they're turned off for catless tunes, but this is leading me to believe that other bank 1 issues I'm having may be related to whatever killed this sensor... or it just died on it's own. I just want some advice as to what might cause this to happen to a sensor.

More importantly, my bank 1 upstream is also off from bank 2 by enough to make a difference. At first I figured it was only on cold starting which had me wondering about my secondary air bank 1 code, but I've cleaned the entire system, had it work a few times, and replaced an o2 sensor on bank 1.

Could the bank 2 upstream be causing issues with bank 1? Bank 1 is running rich even after warmup. I don't even care about the secondary air thing anymore. I'm just concerned that bank 1 is running rich too often. On a cold start, I do notice that the bank 1 upstream responds faster than the bank 2, but still runs rich which leads me to believe that although it isn't important, my secondary air insufficient flow on bank 1 may not be with that system, but just related to the car running rich since my sensors still detect the wrong AFR.

In short, can a bad bank 2 upstream cause problems with the bank 1 AFR and has anyone experienced anything like this?

[tbrown1985]

maybe a sticking/leaky injector? just a thought