I agree, for myself at least, the fecal breath is an overgrowth of bad bacteria in the bowels. I happened upon something that has helped SO MUCH! It is enteric coated peppermint oil. I read about it on the Candida Forum . I got mine at the health food store for about $12. Take one 3 X per day between meals. If your problem is caused by bacteria, it will really help. The peppermint oil kills the bacteria. The enteric coating gets it into the bowels instead of the stomach. This was VERY effective for me and a lot easier than your Grapefruit-Seed-Extract enemas! :)
You can't use it forever, because the bacteria will get resistant to it. You have to build up your good bacteria by taking kefir, yogurt or probiotics. I kept having trouble building up the good guys. Finally I tried Inulin. I was afraid of it because I had heard it would feed the bad bacteria too. I am trying it cautiously and it seems to be helping.
You also need to avoid sugar, as this will feed the baddies too.
If anyone gives this a try, please let me know how it works.