I have a SW gauge reading zero under the hood. I'm installing a low pressure fuel switch 4 psi with the new system. Turned on the electric pusher pump and motor recovered. It happened at idle after a local drive and I was able to see the empty bowls, low fuel pressure, and crappy idle.
Sounds like vapor lock on the suction side. Putting the line under pressure rather than suction should help alot.
When I've had that problem, it was also after idling and the worst was after stuck in traffic on interstate and a very warm spring day with winter blend.
I've added several layers of insulation and a shield to the lines back to the cross member. I also keep some 'storage fuel' on hand, which might happen to be in the gas tank when those conditions are present.
You prob won't need to do that with the pusher setup.