How do you check fuel pressure on 1992 cadillac?

On the fuel rail ( there are 2 fuel rails that connect to the injector bodies on v-8 cars, only 1 will have the valve) there is a small Schrader valve, if you are familliar with putting air into tires this valve should be easily seen. Take the valve cap off (don't loose it though) and attach a fuel pressure meter, these can be bought or in some cases rented from auto parts stores then start and run the vehicle with the meter attached, fuel pressure varies by model and engine size so be sure to look up the correct fuel pressure for your exact engine and year. If your fuel pressure is off you should start by replacing the pressure regulator, not the fuel pump.