1991 Cadillac Brougham Fuel Pressure Regulator Location

Is the fuel pressure regulator located beneath the intake cover or is it located behind the injectors in the carb. I am wondering cause I am trying to figure out if my car is running rich or if oil is leaking past the seals. I get the black soot out the exhaust and my spark plugs are fouled and they are carbon covered and I can clean them off and use them again. I just need help in figuring out if its oil in the cc or if its a rich fuel mixture. Please help.