If your car has a fuel pressure regulator, there is a very specific way that you need to go about releasing the pressure from the fuel system. First, you will need to find the fuel pressure release valve, which is usually located on the fuel rail. Once you have located it, you will need to use a fuel pressure gauge to release the pressure.
Attach the fuel pressure gauge to the fuel pressure release valve and open the valve. This will release the pressure from the fuel system and allow you to safely work on your car.