Thank you for getting back to me. Smoke tests done, no leaks. Plugs and wires are good, spark test also done. Codes are just as mystifying, keep changing. IAC is next. EGR ports. Maybe lower manifold gasket? Yesterday ran like a charm, no issues whatsoever. This backyard mechanic'ing in winter, when you don't know what you're doing is getting old. But I will prevail! Fingers crossed it is before it drops to -40 again.
Maybe a $2 fix? clean fuel injectors? I will be happy but pissed if it works.