The code I'm getting isn't a cat efficiency code, which is further evidenced by the fact I still have the code on a test pipe tune.
According to MHD, using a spacer is dangerous and shouldn't be done. Apparently they use the downstream O2 sensor in their tuning strategy
I have a super annoying CEL after installing the ds-1.
12BB01 - oxygen sensor after catalytic converter, from lean to rich: delayed response.
I've tried aftermarket and stock downpipe tuned, and I changed the O2 sensor. Code persists. Any clue what could be causing this?