I have been having the same problem for quite some time now. The only way I could get it to start was using either and once it started it ran fine. I changed the fuel pressure regulator and still the same problem. Just recently I had to change the intake gaskets because they were leaking water. I still have the fuel pressure problems but now it will start on fuel after 4 or 5 attempts.
I get 60 psi when the pump starts and as soon as it stops fuel pressure goes to zero. I am wondering if it isn't the Fuel Tank Pressure Sensor. I have a used pump here and I am going to try that and I will update once I find out.