i would highly recommend having the fuel system pressure tested using a fuel pressure gauge. since it was working good for a couple days, it is very possible the new fuel pump is defective. the only way to know for sure is with a fuel system pressure test.
replacing a fuel pump in the gas tank is no fun, i know, and having to do it twice is a pain.
hope this helps, good luck.
Disabled American Veterans (DAV), remembering those who've served.