FiTech EFI system

Soooo, It's running ,, but at idle with IAC at about 7-10, every 30 seconds or so, it drops down to about 400 rpm and the IAC opens to allow air in to recover to 12 to 1300 rpm before it settles back down, and so on and so on.

Seems like a vacuum leak to me, and probably a PCV valve that is hanging open most times, and then slowly shuts down, cutting off that extra air and driving the rpm down until the IAC allows air back in.

Am I on the right track ? I will take the PCV valve out of the equation later for the next test.