i noticed on my car it doesent start first time when i crank it over.
But if i take the gas cap off and relive the pressure it starts perfect first time and drive fine until the tank get pressurized again.

Its not a vacuum its pressure.

I bought a new gas cap, nothing.
The fuel line is good, also there is another line that goes from the fuel pressure regulator to the tank. I blew in that line and its clear, besides the gas thats in the line...

Any ideas?