TBI sprays too much gas

Instead of a cone of mist, I get niagra falls spraying into my engine. Usually accompanied by a loud hissing sound which usually ends with a flooded engine. How can I tell if it is a problem in one of the sensors, or what not. I have a 350 vortec engine(1998 suburban) inside of an Iroc with a holley TBI 2 barrel. Some say its the throttle position sensor, some say the idle air, and some say the computer. I dont know man.