my 95 apv lumina 3.1l misfired around 40mph and shut off around 50mph

I replaced a new ignition module, while I replaced it I noticed the connector to the module has a broken plastic casing. Can it be the cause of the engine misfired around 40 mph and shut off around 50mph? can it be electric arc between the bare connectors.

It sure can.

I rubberized all connectors and change the pickup coil and the car still misfired around 40 mph but if i slow it down and start to accelerate slowly, there no msfired. Last diagnostic test using OBDII said Low voltage fuel pump.Is the fuel pump can cause this problem?

Low fuel pressure will exhibit the symptoms you describe. If the voltage to the pump is low, it will not operate at full pressure, causing a bog or hesitation, especially when accelerating or when under load. I would inspect the fuel pump relay (and it's harness) to be sure there is no melted wires or corrosion before buying a new pump. Also, check the wiring to the fuel pump for the same conditions. If the wiring checks out, you may need a fuel pump.