Here is a list of possible solutions not in any order.

• Number 1 problem would be the ignition. Check plugs, wires and distributor.
• Clogged fuel filter
• Weak fuel pump. Test the pressure.

Is it dying because of too much gas?

• Look down the carburetor after turning it off. Is any gas dribbling down the venturi. This would mean gas is getting siphoned from the float bowl because of non vented gas cap, carburetor vent(s) plugged off.
• Float may be bad or out of adjustment. It may be allowing enough fuel at idle but runs out at higher speed.
• Needle & Seat leaking.
• Is the choke closing when cold and not opening all the way until warmed up.

Is it dying because of not enough gas?

• Kinked fuel line.
• Gas tank too low (not likely but have heard of some not working when gas gets too low.
• Rubber fuel line collapsing because of ethanol damage. You would probably see black particles in the float bowl.
• Dirty carburetor. Do you see any dirt in the float bowl when removed?
• Has the car been sitting for months at one point? Gas will turn to varnish and coat the inside of the gas tank and carburetor. Fresh gas will not fix this problem.