have cough with sulphur taste since Nov. 2012. two rounds of antibiotic and prednisone helped but both times it returned. Cough has been very productive especially when deep, heavy attacks occur once every day or every other day. Consistency is like peanut butter at times, but usually always thick. Color ranging from bright yellow to tannish color. Quit smoking 5 yrs ago. Never had cough til now but always clearing throat, sometimes almost choking on "something in there", but figured it was allergies, which I suffered from as a kid. Chest x-ray last month was clear. Lungs sound clear to doc. In last week or so seems as if productivity is much less but I still taste sulphur. Should I be concerned? I am a 54 yr old female with a great family I am not ready to leave behind. Having cat scan w/dye today. What is next step if nothing is found?