Here's an experience I had once in an apartment where shared bath with
an elderly lady. The toilet would stop almost total one time and then
work fine maybe two or three times then stop again. Ran a plumbers
snake thru it and couldn't find anything. This kept happening till I
finally remove the unit from the floor. I found the culprit. Was the
lid of a tin can that was almost the size of the drain tube in commode.
It had lodged there and was acting sorta in a butter fly manner. It
would close then it would open. Apparently the elderly lady had dropped
it in there and didn't notice what she had done.. It was a mystery
situation till I took it apart though
Jack.