The fuel pressure sensor is a little black plastic device on the end of the fuel rail as it exits the fuel rail. There is a vacuum line & electrical plug on it. This went bad on my car this year. It cost about $20.00 at the Ford part counter. This is not covered in the Haynes manual either. There is a diaphragm that checks pressure and sends an electrical signal back to the plc (main computer) and tells the computer that the fuel pressure is ok. This has nothing to do with the fuel pressure regulator or the fuel pump. Remove the throttle body, the little buger is under there. This will cause the car not to run due to the diaphragm breaking and fuel being sucked into the intake causing a rich condition, at least in my case. Hope this helps!!!
