97 Sierra cold start

I have a 1997 k1500 with 5.7
Forgive me if this has been discussed before.

This engine is very had to start first start of the day.
Cranks fine paritially attempts to fire.
Following procedure in a chilton manual for fuel pump test I am still
uncertion where to go next.

Key on /Eng off pressure is 62psi at rail
Key on/Eng on at idle 53 psi
Key on/Eng on rev to 1500 rpm jumps to 61psi.
Pinching the return line no change in pressure no mater engine or key state.
Fuel lines that are visible are dry and rust free also no fuel smell. Engine
runs fine and drive ability is good once started for the day
I not sure at this point where the problem lies.

Thanks in advance for your help.