I get the same exact thing on two of my cars, and it doesn't seem to have any effect on how they run whatsoever. And they're two totally different engines.
One's a 455 Pontiac, with a mechanical fuel pump, in a 1968 Firebird, and the other's a 427 big block Chevy in a 1968 Corvette with an electric pump.
I can only guess that when the fuel vaporizes in the line, it causes the pressure gauge to read zero. But why it doesn't run out of gas that way, that's what I don't understand. So I'll be watching this post to see if someone knows.
