Sometimes when running for a while, especially on less than 1/2 tank of gas, I hear a buzzing coming from the gas cap cover. It is as if pressure is building up inside the tank, and the resulting air pressure buzzes against the key cover. The real problem is that sometimes the air pressure forces a small amount of gas out with it, today causing gas to actually leak onto my jeans. Is this a gasket/seal issue, a bad tank, or just something to live with? It seems to happen when the tank is either completely filled, or almost empty.

 

I have never had that happen to me or even heard it. What I imagine is happening is your vent hose is clogged up and can't release the pressure that builds up probably from the tank getting warm due to the motor. I would take off the tank and check to see if the vent hose is clogged or not. Its on page 5-56 on the service manual.

 

+1 to R-Dub... That seems like a pretty big problem.. The Two Hondas i have own never done that!