AFR difference between the banks

Mitco39

HC_416,

I dont think any exhaust leak would cause this. The ECU knows its running rich but yet its still trimming like its lean. Even if you had a big leak the ECU should do whatever it can to meet the target AFR, not push itself away from it.

Do you have a cat delete? are both downstream O2s roughly in the location they would be stock? I have a BP kit and both of my downstream O2s are actually in one bank. I think this might be causing my issue, however if I can find someone else who has both his 02s approximately in their stock location with this issue then that would rule this out.

The way I see it aside from the possible secondary cats causing the issue there is nothing else on the car that could possibly contribute to this. A pin hole leak or even a big leak would make the ECU work overtime to meet the target AFR, not push itself away from the target. If that makes sense.

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