OK so I just recently got an 89 Mustang GT, and am working on fixing it all up, and have run into a problem. Whenever I accelerate quickly, the car will lose power and will backfire quite a bit and will just not doing anything. If I accelerate gradually it won't do it, but that defeats the purpose of the car and ain't no fun lol. I have been told it is the fuel pump, but don't want to go out and spend 150 bucks or so right now for the one I want and it still has the problem. Any help will be appreciated 
Also when it does start, you can hear the fuel pump really good whirring in the back when inside the car, and with the exhaust system on it, its pretty loud to overcome that