the sending unit has zero to do with how it runs [unless it tells you there's gas when it's empty

], I say definitely a fuel problem, unless you have some electrical ignotion connection that 'opens' when it gets hot and then immediately makes contact again so the truck restarts easily - as CASO says, the engine just isn't getting strong enough fuel flow ... have any rubber lines in the fuel supply line been changed out for new? internally deteriorated hose can collapse and limit flow
Bill