hello i own a 1995 cadillac deville . It is a 4.9 with a v8 poi (not a northstar). Recently my engine has been diving on me while driving. I have to drift to the side of the street and park. I then have to give it a few minutes and it will start back up again. I did do a fuel pressure test and the fuel pressure does not stay consistent in the 34- 44 psi range. Instead it sinks down and falls below 20 psi within 10 minutes. Note: this is one in the on position. I then turn the key and start the car the fuel pressure jumps to around 40 and will stay near there until the engine completely cuts off and there is not longer an pressure. I check my fuel pressure regulator and it seems to be working. i also changed my fuel filter, fuel pump fuse and relay. I don't know what steps to take next and i really need my car back and working Please someone help mechanics are to expensive at the moment for me. Please help ?