Will increased oil consumption (rings, valve guides, etc) give false O2 readings (rich or lean)?

 

Depends.
Oil is has a low octane rating. So if your using enough of it, then it will be setting off the knock sensor, and running a false, *rich*, due to the retarded timing.

As far as the PCV system goes it will pass more *air*/*blowby*, so the MAP might read *slightly* high.

I think that's what Doc was trying to say...