It was the fuel pump the whole time

You also may want to check the pickup tube inside the tank. If the pickup screen is missing or corroded it'll suck up any debris in the tank and clog your new pump really quick. This happened to me, I refused to believe the new pump was bad. Turns out the tank was really rusty and full of crap so I replaced it along with a new screen and shook all the garbage out of the pump too. Works great now.