My toilet has a steady stream of water coming out of the main jet in the bowl. I replaced the flapper. The chain is at the correct length. Nothing. I replaced the whole flush valve system, including another flapper. Nothing. I replaced the toilet fill valve. Nothing. Everything is at proper height. The flush valve is 3" lower than the top of the fill valve. The fill valve is at least an inch lower than the handle hole. The fill line is cut to the right length and is above the fill line. I have cleaned the jets coming into the bowl. They aren't perfect but they are clear enough.

Now get this. I empty the tank to below the flapper and then I shut off the water and disconnect the hose. The toilet STILL runs until ALL water is removed from the tank and then even for a little longer. What the heck is happening??? Please help!