Maybe a mouse found its way into your ductwork and died....................or some one hid a dead fish in it ...............or ............it was previously owned by VIKINGS............you will just have to start sniffing around and locate the problem. <_<
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Really. Well, after doing what you “suggested” oh a long time ago I was hoping to get some feed back by some one who knew what they were talking about. Before I take it into a shop and get a run around by someone who wants to take advance of my lack of knowledge, being a girl and all. Sorry, if I sound on edge, but this is a real problem, it stinks when in use. But thanks anyway.