cutting out going up hill?

Could be a lot of things, 'specially if you don't know what was done or the history.

Connector hoses. There is one from the fuel sender to the main tube at the tank, another from the feed tube to the pump inlet. Replace them both.

Refer to the shop manual and test the pump Get yourself a vacuum/ pressure gauge, not expensive.

If the pickup does not appear to have been replaced, I'd suspect the screen in the tank.