A few possibilities here that I can see. First, your fuel pressure could be too high. You'd be surprised how many brand new fuel pumps bought from auto part stores have way too much pressure. I've seen as high as 13 lbs. You need not to have more than let's say 6 psi.
Also, if you have a dead end fuel system, you should seriously consider having one with a return line. I've seen many many cases where this solved all the hard starting problems while hot.