thick, sweet hot&sour soup in Philadelphia/Main Line
Here you go: the most disgusting hot and sour I've ever had (which matches your description...) is served at the KOP Mall food court - the bigger of the two malls, on the second floor. I think it's called Master Wok, and there's another Master Wok location at Liberty Place.
And you'll also like the hot and sour at China Palace (?), a little hole in the wall on Rte. 30 in Wayne, right before the Whole Foods.