Is the fuel system in a 1995 gmc vandura 2500 pressurized?

No, the fuel system in a 1995 GMC Vandura 2500 is not pressurized in the same way as a modern fuel injected vehicle with a high-pressure fuel pump. It uses a return-style fuel system with a lower pressure fuel pump in the tank. While there's some pressure, it's significantly lower than what you'd find in a modern, common rail, or even many older multi-port fuel injected systems.