fuel pump? regulator? help!
 

I have a 96 camaro 3800 v6, I replaced the plugs, wires, coil packs, fuel filter, and it runs a lot better, not missing like it did, but it still seems like it misses at heavier throttle, it stutters and chugs.. my fuel pump in buzzing kinda loud so I'm thinking it may be that, I disconected the vaccum line on the fpr and didn't notice a difference, didn't see any fuel.. but I did notice that the thing the vaccum line from the fpr conects to, right below it is other vaccum lines and it has an electrical plug, not sure what its called, but the very bottom line is missing, its just the boot that the line would go into, but I can't find the line anywhere.. could this be my problem? Where would the line come from that would connect to it? And if this isn't the problem should I start with the pump or regulator first? I dnt have a pressure gauge so I can't check that..