93 GMC K1500 with a 305 TBI and it is running way too rich you cannot get the engine to start without fully opening the throttle And when it finally starts the exhaust is very dark?

Answer sounds like a fuel leak more than likely the fuel pressure regulator or the fuel injectors. I had a similar problem with my 1991 Silverado with a 350 TBI . After buying a coolant temperature sensor "The one on the intake manifold which acts as a choke" , I had no further problems . May also be a map sensor . I had similar problem on a 1989 Chevrolet Blazer with a 305 TBI. http://www.autozone.com/N,15900113//shopping/partTypeResultSet.htm