ZDriver.com - Fuel/ Maybe air/vacuum issues

First off the car I'm having the problem on is an 87 N/A. This problem has me stumped. Recently I have replaced the fuel pump relay, fuel filter, Gas cap and tonight I just changed the 2 short hoses that were worn bad coming from the fuel pressure regulator. Anyways, the other night I was riding the highway and the Z cut off and all the warning lights came on. I pulled to the shoulder and could get it running again but it would shut off after a while. I got it running and tried driving slowly but it cut off. Got it on and basically floored it and stayed running all the way home. Since then I've had no problems. Otherwise, before the highway situation which was yesterday night, it often had trouble firing up and would just bog itself down or cutoff. It's my daily so while I'm happy it's fine now, I feel as those 2 hoses didn't actually fix the problem? I'm trying not to assume it's the fuel pump itself because I'm still able to drive but the problem comes and go. Thanks for your time to read this and any help or advice you may have! (Sorry if I posted in the wrong area, this is my first time being active on the forums! :083:)

Addition: Things that might also affect/cause the issue: I had about a 1/4 left in gas and after I filled it a little under 3/4 no issues, again I have no idea if this is the cause or if it was just luck. Lastly, when I completely fill the tank, gas leaks around the top of fuel pump so I'm sure the gasket or o-ring is bad.