air in fuel line/leaking injection pump

[paolomarks]

I have a leaking top gasket on my injection pump (98 Jetta TDI), and there's clearly air in the line, going into the fuel injection pump.  I believe the air in the line is causing an intermittent loss of power when working the engine uphill. Is it possible that the leak from the injection pump is the cause of the air in the system?  Or is it more likely taking in air around the fuel filter?

[8v-of-fury]

What about the line going from the pump?? is it full of air too?