96 suburban fuel problem, please help

Ok, so i recieved a 96 4x4 suburban from my brother, it had been sitting for several months and was hard to start. i added injector cleaner.
eventually it quit starting all together, we found that it had plenty of spark but no fuel. I replaced the fuel filter and still no luck. I then deduced that the fuel pump was bad, after replacing the fuel pump it started up like a champ, FOR A DAY! Then it became hard to start again, and then quit starting without help.  Now if I pour gasoline into the carb, or spray starting fluid (very little) into the air filter intake hose it starts up quickly and runs great! I have to be missing something, a sensor or a thinga ma jiggy or somthing, any help is greatly appreciated.
 
Chris

It could be a lot of things being a donated vehicle.  I would take it on a long trip to burn out the old gas, and stomp on it while doiing it.  I would check the quality of the gas.  An easy spark diagnosis is hooking upa timing light.  I would  put some Stabil / isopropyl dry gas in it to break up deposits from dried fuel and remove water from it sitting.  After that, I would look at the spark plugs and do a compression test.  Is the battery okay?  Have you peaked at the distributer cap and rotor and air cleaner?

Could even be the fuel pressure regulator.

Check the wires at the fuel pump something the ground wire be bad.