What is your battery voltage, engine off and engine running? Does it continue to run after intial starting fluid? What is your fuel pressure key on,engine off?
it continues to run after starting with fluid.battery voltage 12.3 fuel pressure in spec
I suspect the wiring is not making good connections, high resistance, low voltage. Did your mechanic replace the wires that came with new fuel pump? Your battery voltage is low. Have your battery fully charged and load tested. Make sure battery terminals are clean on both sides of the bolts that scew into the battery with no corrossion. Check or replace battery cables. Your battery voltage should be at least 12.6 engine off or 13.8-14.4 engine running.
You cannot properly test a battery if voltage is less than 12.4 volts.
I'll have to get back to you on Mon.It isn't the battery,he had a new one in and all of the connections are clean.Could it be the starter?