A bad connection at the ICS plug could will cause hard starts, back firing, and hesitations. A faulty EGR valve or EGR modulator will cause hard starts, and hesitation at certain rpm ranges but go away while accelerating.
Also realize that the carb often gets the blame when other components are the culprit. How do you know it's the carb? Faulty ignition systems, bad plug wires, clogged fuel filter, leaking and failing fuel pump or fuel line, bad gas, dirty gas, water in the fuel, trash in the fuel all lead to...