1994 Ford Bronco 4x4 with 5.0 wont start?

Here is what is going on. I can crank over my bronco all day and it will not start. During the first few cranks it almost started but doesn't. I have checked and I know that I am getting spark. I can get the Bronco started with starter fluid. When it does start it will run without any problems. If I turn the engine off before it is hot, it will start again. But if I turn it off after the engine is hot, then I need to use started fluid to get it started again. I have already changed out the fuel filter. I have some people telling me that it is the fuel pump but I was wondering if it could be something different because a fuel pump is expensive and a pain to change. I have about 3/4 a tank right now. When I turn the ignition I can hear the fuel pump buzzing but it sounds abnormally loud. Please help.