As this is a '84,truck, does it have the accel pump soleniod in the right frt corner of the carb ?? If it does, try to disconnect it and see if it's any better. Sounds like the idle mixture screws may be too lean. Have you atempted to adjust them. Preset years ago was about 2 1/2 to 3 1/2 turns on a Q-jet. Possibly a low float level (most Q-jets set at 1/4 "). D