85 tpi 305. Hard to start after sitting overnight. Once i get it started it has a rough idle for about 5 minutes then idles normal. I've hooked up a fuel pressure gauge to the Schrader valve on the rail and get 35psi when the pump primes but once i turn the key off it drops to 10psi then 0 after about 5 minutes. Has new filter, pump, and regulator. I've pulled the rails and checked the injectors and no leaks. What else should i check?

 

Fuel Lines and Fuel Pump.