Stalling when warm issue

Okay today replaced the rubber fuel line from the steel line at fire wall to fuel pump. Still did its usual died once it heated up, I think my next jobs will be remove the steel line from the car, and blow it out or replace it and install the spacer at the carb. I let the car idle in drive for a while, even though temp. gauge never went past 200, once I turned it off, I could only touch the base of the carb for about a second or so. Still the question remains, once it cools down and I start the car it has great fuel pressure, once I pull into the drive, after it has been driving awhile, no fuel pressure and it wants to die..... I am all into the perculation idea, but why do I have little or no fuel pressure when it warms up?