300zx z32 gas tank not building pressure

[Azazel703]

My 300zx is gas tank isnt building pressure in the tank is that ok? All the other z32 ive had every time i would get gas i would hear air come out when you lossen the gas cap but this z doesnt do that. Also my fuel pressure is around 30 psi at idle and goes up to about 40 psi when you remove the vacuum from the fpr. My z is a 1990 na-t