What causes sulphur burps/vomiting, diarrhea episodes?

     What causes attacks of SULPHUR BURPS followed by vomiting and diarrhea lasting for hours?  I have had this problem for years, but lately it has become chronic.  I'm on a low residual diet (no raw fruits or veggies-only cooked or canned).  It helps a little.  I have to sleep propped up in almost a sitting position which is miserable.  My G.I. doc doesn't know what is causing it.  He ran an endoscopy, an enteroscopy, and an ultrasound and found nothing.  Now he is going to do a colonoscopy.  
     One thing to note, I have Fibromyalgia.  My G.I. doc says a LOT of people with FM have GI problems.  FM is caused by a genetic liver/kidney disfunction, so there could be a connection....
     Does anyone else with these symptoms ALSO have Fibromyalgia?  Has anyone found ANYTHING to succesfully treat the GI symptoms mentioned above?  There is no cure for Fibromyalgia, but there HAS to be something to at least TREAT the GI symptoms!  
Hoping for an Answer,
Andie