92 Chevy Astro van

My 92 astro van died the other day. It acted almost like it had run out of gas. We left it where it died over night, and tried to start it the next morning when we went to have it towed and it started right up first try. We went to drive it again after leaving it run for about a half hour it did the same thing. We let it sit for 2-3 hours then tried to get it home it drove real rough for about a mile then died again. We've checked the fuel filter it is not clogged. There is gas in it. When turning the key on you can here the fuel pump cycle or prime whatever it does, but not every time 1 out of about every4-5 turns of the key can you here it. Could you lease point me in the right direction. Teena CA