The fuel pressure regulator is located at the end of the fuel rail with the fuel injectors. It will have a vacuum line attached to it. If you want to check it install a fuel pressure gauge see what the pressure is at running(53-59psi) unplug the vacuum line and if it is working the pressure should increase 3-5 psi. That means its working. Or test it with a vacuum pump, apply 12-14 in of vacuum, should hold vacuum. Post back with any other questions.