The bathroom tub and sink drains (upstairs; haven't used the downstairs bath) have this problem where they act like they're clogged at first and then an air gurgles up and they drain normally again. Doesn't happen all the time, either.
Mike
You have never used the downstairs bath ?
I'd suspect some sort of massive hair clog. Figure out how to get a snake in there, or locate the cleanout.
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