Ya know on many MANY of these posts I see a shotgun approach.
Do you have a shop manual? There is actually a pretty good diagnostic procedure to troubleshoot the pump.
Do you have a vacuum gauge? Even in this modern age, a test vacuum ga/ fuel pump pressure ga. is just not that expensive.
You need to suspect:
Obstructions in the line/ pickup, including old hose sucking shut, and debri or other problems in the tank/ pickup
Vent problems at the tank
The fore mentioned pinholes in hoses and tubing
A bad pump that cannot pull enough vacuum
Could even be a worn pump cam/ lobe/ pushrod/ arm