1996 Chevy Astro No start after a cold soak/after sitting a

Hi, my name is Nick, and I just purchased a 1996 Chev Astro Van from a friend. After a few days, the van wouldnt start! The van wouldnt start after sitting all night, but would start after the engine was running a while. After removing the "Doghouse"to get to the rear of the engine, and removing the upper and lower radiator shrouds(Made it easier to service the cool system and check for leaks), and also removing the intake air ducts and air horn cover, I started troubleshooting the problem. I first checked for spark at the dist cap, and had a strong spark.I then checked for spark coming out of one of the cap terminals, and had an weak, erratic spark. So, I removed the cap, cleaned up the inner terminals, replaced the rotor, put it all back, and it still wouldnt start! The spark coming from one of the plug terminals was a lot stronger though.I then poured a half a cup of gas into the throttle body, and low and behold the van started! The van starts EVERY TIME after doing this. So I think the fuel pump is bad! During troublshooting, I stuck the tip of a screwdriver in the fuel shraeder valve(While eng was off of course)and had very little fuel come out, and no spray. All this is with about 1/3 of a tank. Could it be a bad pickup in the tank, a bad rubber hose coming off the pump, or a bad fuel filter. I also checked all the fuses, and they were all good. I'm also thinking that the injectors might be clogged up. When I reached inside the throttle body, with my fingers, I pulled out a lot of red sludge! Before spending $140 on a new OEM pump, I was going to run a good fuel cleaner in the system, and spray a couple cans of carb/throttle body cleaner, and see if the problem decreases or goes away completely. I'm also going to check the fuel pressure while cranking, and while running.