distributor failure????

Would using an msd external coil and cap cause the distrubutor to go out? Would the external coil cause any problems?? My car is hard to start and when i floor it from idle it’ll come close to dying and if i keep it floored it will die. I’ve repalced spark plugs, cap, rotor, fuel pump, coil is external, o2 sensor and the fuel filter. the only things not stock are msd wires, cap, and external coil. I also remover the lower half of the air box. What could it be???