1979 Ford Pinto mechanical problem question...?

Strange problem with my 1979 Ford Pinto. Car idles well but sometimes when driving (usually between 35-top speed) it chokes and misses. I can let off the gas pedal and finesse it a little and make it stop but it will do it again at random. So far I've changed the alternator, cap, rotor, plugs, wires, air cleaner, cleaned the carburetor and plugged the vacuum line to the EGR valve to byp it. Anyone have any other ideas on suspect things to test out?