hi! I have the exact same problem for over 10 years. I've seen doctors, done cat scans..all in vain.
The only thing i do to make the smell go away for a while (or sometimes for all day) is a nasal wash with water for a minute or two till it disappears. Unfortunatelly for me it got more frequent and consistant over the years.
A doctor told me yesterday, that it might have something to do with my demyelination problem and I will search it...
I've been googling it all day today and discovered that it could also be ozaine (akaAtrophic rhinitis) or parosmia (http://en.wikipedia.org/wiki/Parosmia). Do you have any answers?
hello...I have the same nasa odor as you described...wondering if you got any answers yet