I'm trying to start it every now and pump will kick in for just a second but will not
Stay on or build up Ny fuel presure . I'm going to try to replace the crankeshaft
Poisoning sensor. If you might have thought of something else let me know
You replaced the filter, the pump, or both. The pump will prime for 3 seconds, if you have a gauge you can verify the pressure, can you cycle the key 3 or 4 times before starting the engine and does it build pressure. Did you install the pump your self or have it done. Don't change the crank sensor until you verify the fuel pressure. If you don't have fuel pressure the crank sensor will Not help you start your car.
If you did it right and have no leaks you will have pressure. Your line of doing 50 doesn't mean a thing to me I've done over 500 in my life and anything can happen. Now if you want my help I don't need you to be so sure you are good at what you have done. Right now is the issue. Double check your work something is wrong. Find it. If you jump the relay it might run longer. Think there is always a way to make it work. The hell with the other parts until this issue is fixed.