Dynamometer Results & Comparisons - Question for Dyno Gurus

I was at the dyno last night with a blown fuel injected small block. I think I am having ignition problems because the car sounds like its skipping or missing at high RPMs. The weird thing is that the car dumped black smoke, but the wideband read 12-13:1? I'm pretty sure the wideband is good because it read right for the car before me and after me.
My question is: Would a misfire or skip produce black smoke, but trick the A/F? :bang:

12-13.1-1 AFR's are pretty lean for a FI application. Normally FI tunes set the AFR from 11.7-1 to 12.1-1 depending on how safe you plan to be.