So Toby has once before had this horrible breathe problem...but it is like a deep gut breath, like nothing I have smelled before - not teeth and mouth (had a full dental 6 mo ago any way). Anyway, the last time this happened the vet agreed that it was something in the guy (a really foul smell) and when he was under for his MRI, she checked everything and found nothing. So she put him on antibiotics and it went away (though we never knew why).

Now this smell is back. Going to the vet tomorrow but any ideas what could be causing this? I would rather find a reason vs. just shooting blind and not knowing. It is such a bad smell, I can't describe it...it's not "bad dog breath" almost a bit sour and metallic kind of...and a deep gut smell.
All bloods are normal, nothing is wrong with the kidneys or anything.

Just hoping for any thoughts before the doctor????