Is the problem with the fuel pump?

First off shakiness while driving could be caused by transmission slippage so check your transmission fluid and put some in if needed. The engine not running right could be the ignition coil, if the timing isn't right or slightly off it would cause the rough ride and not running right. If a wire or something going to the ignition coil is slowly loosening it would explain why your father's caveman hammer hitting technique worked, it simply reconnected the wire. Maybe check the engine mounts too to see if their loose, that would cause shaking in the car too. It could also be the fuel pump, if it's not getting enough fuel pressure in the injectors then it would run but very rough, the garage should be able to test the fuel pump pressure and tell your weather it's good or bad, if it's good then you don't need one, if it's bad then you may need a new one, or check for leaks in the fuel lines.