Assuming the pump you pulled out looked all shiny and new, I am gonna assume the shop replaced the in tank pump, and maybe it really was dead. But it did not fix your problem, because it was not the cause of the intermittent dieing and then restarting. It was A problem, but not THE problem. I have run these two pump models with a dead in-tank pump and barely even noticed it until the tank is less than a 1/4 full. I am gonna take a wild guess and suggest the "Power Stage" or ignition amplifier is pooping out on ya. Don't get me wrong, if the in tank pump is dead, replace it. But I would pick up a JY spare Bosch or Knock off version FCP sells and carry it around....just in case. Time will tell, good luck.