It's hard to read on my phone.
The latest data you have is from four years ago?
I'm thinking the thermactor pump or check valve is bad.
CO should be burning off in the exhaust manifolds if fresh air was being pumped into the exhaust ports.
It may be as simple as a PCV for high HC, or maybe a valve seal...
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.