Hey my dishwasher all of a sudden started spewing used water from the air gap on top of my sink. It is connected to a garbage disposal although the disposal seems to be working properly at this time. The dishwasher works great except form this new symptom. Believe it or not this really just happened this morning. We run the dishwasher daily and have never had a problem .

You have a blockage in the hose between the air gap and the disposal. Remove the hose and clean. Check inlet to disposal.