1987 Nissan Stanza won't start

Its the 4dr sedan, approx. 100,000 miles, 4 cyl automatic. I bought the car to fix up. The people I got it from said the fuel pump was bad, but then I noticed it had a fuel leak by the gas tank, so i changed the fuel line and got that fixed, and replaced the fuel filter. When I start it, it'll run fine and idle good for maybe about 30 seconds, but if I try to give it gas and rev on it, it'll die, and then it'll start idling really low and keep trying to die. Could it still be the fuel pump, or probably the fuel pressure regulator? The cars also been sitting for a couple yrs at least so I know its gonna need a tune up. Just curious about the giving it gas and it not doing anything and dieing. Thanks for any help you can give.