had flappers and other parts replaced last year, now in the past few months the toilet does what I call a long burp and quite often, it doesn't do a flush on it's on, but sounds like it. When i run a faucet somewhere else I can hear the toilet do it's thing..driving me nuts..is there a pressure, or air problem or what is going on? Two toilets have started to do this. if you can also email me that would be great..preceptna@aol.com Thanks