I betcha this o2 sensor is related to the header

these y7 exhaust systems suck....

when I first was throwing a CEL dealing with my EM, I went to a honda-certified mechanic who checked out the code for free. They told me it was the primary o2 sensor, related to the EM having thin cracks near the o2 sensor. They shut off the CEL for me, and I went along my way.

3 months or so later, I was throwing another CEL, but this time I had honda take care of the shit under their extended warrenty (I posted a thread about this not very long ago), and when they were reading what CEL was going off, it turned out to be the catalitic converter.

However, I remember you already replaced your exhaust manifold recently (got it with a transmission or something? is that you? ). I've heard about o2 sensors on these 6th gens going faulty, but I thought those were primarly a problem with y8's....

eh, I doubt this helps h: