When I flush the toilet a large air bubble comes out of the flush jet hole and the result is that the toilet does not flush properly. I do not think the line is clogged past the toilet as I dumped approx. 20 gallons of water into the toilet as fast as I could and it drained faster than I could pour it in. Also, it is not the make of toilet that is the problem as I have 3 more of the same toilets in the house and they all work properly. The problem appears to be between the toilet tank and where the water exits the flush jet hole. Any ideas as to how to correct this problem?