Anyone ever have an issue with getting fuel pressure but the car not maintaining it?

Engine running or engine off? 

Engine will not turn over. It cranks but wont keep fuel pressure long enough to turn over.

Here is my exact situation. I have a 1997 legacy outback with the 2.5 dohc. The other day it would not start. So i hooked up my reader and it said that the crank position sensor wouldn't read. So i replaced it and now there are no codes. However, when i turn the car on the fuel system has an issue. The pump does engage for a few seconds and pumps up to about 40 psi. However, it doesn't hold that pressure nor will the pump stay running when the engine is being cranked. Replaced the pump and still the same issue. Can not see any leaks anywhere. Any ideas?

What was the code number?

 

When it cranks does it crank fast? Sound smooth? You should be able to count 4 chugs in a row. 

 

Fuel pump only runs to prime the system, it will only continue running if the engine starts. If the engine doesn't start the ECU turns off the fuel pump relay. 

P0335

The sensor had a broken connection due to a broken wire. That was repaired and there is no longer gives the code. It cranks at a normal pace it just doesn't try to actually turn over. 

Spray a small amount of starter fluid into the intake to see if the engine will run on that. If the fuel pump won't turn on the pump relay may be a reasonable bet to replace.

Probably not getting spark.

The ECU uses cam and crank sensor both to determine crank position for spark and fuel, both need to be working or you get no spark.

Recheck your wiring connection. The crank sensor wires are sheilded, (grey jacketed wiring) you have to make sure the silver sheilding wire is NOT touching the copper signal wires. The sheilding wire is grounded and if it touches the signal wire it shorts the sensor so the ECU doesn't get any signal from if.