I'd be interested in seeing your cam card too! I was watching this happen here to in last log but not convinced it is the cam yet, I think there are other issues.

What your describing is to much cam for EFI CL Idle, either duration or overlap and your getting reversion/EGR at idle. there's a point where you can't raise idle, advance timing and lean fuel enough to get good exhaust to O2 sensor. The Narrow Band O2 sensor is lieing, or more acuratly being lied to. When that happens Open Loop Idle is the answer! As you found.