Fuel problem

Okay,this isn't about my Mustang,it's about my girl's 1985 Jeep Wagoneer.

Gasoline isn't getting to the engine.Now her step-dad has done the folowing:

-replaced the fuel filter
-replaced the fuel lines
-replaced the carberator

The only other thing I can think of is replacing the fuel pump.What do you guys think,can that be the problem?