Check fuel pump relay and fuel filter(filter is by gas tank toward front and the relay is on driver side of console by steering column) .You can try to clean the tank with a chemical solution from any automotive parts store.
Or try this other parts to check which I only got from Geo repair questions
when my cousin had a quite similar problems as yours.
1: engine compression , 180psi on all 4 , if all way less then you have a serious problem.
2: check fuel pressure.
3: check injector signals with a NOID light.
4: check spark first.