Telman
Sour breath is often a sign that the problem is in the bowel, gastroenteritis,
The sour breath can be accompanied by abdominal fullness, gas, abdominal distension, abdominal pain and cramping, feeling sick, difficulty passing gas or stool (constipation). Bear in mind the constipation can be hard of soft stools.
Because you are so good with your nutrition it may be how you eat rather than what you eat. Have you considered "food combining" to try and diagnose the problem?