1991 Isuzu Amigo It doesn't seem to be getting fuel

I can drive the car in the morning with no problems. but if i stop, the idle speed goes down and, it the gas pedal doesn't seem to work. i have to pump the pedal quite a few times to raise the engine. even then it jumps like it's not fully in gear. when i depress the clutch a gun the engine it moves. whats the problem.