low fuel pressure

I have a 96 chevy truck 1500 series - 305 vortec - csfi fuel injection. My problem is when i'm driving and let off the gas I have a hesitation. This is a project truck I drive on week-ends. This is all I have done to fix it. I started with a tune up, dist cap.wires,spark plugs, rotor,new fuel pump assm, new fuel filter, new csfi (spider), map sensor, temp sensor, mass flow sensor, air temp sensor, egr valve, tbi sensor,air filter, fuel regulator twice, all sensors on exhaust, new exhaust,cat. I,m only getting 50 psi at rail, when I dead head it it goes to 73. Any advice would be appreciated

Does it hold pressure?

Check the fuel pump ground wire on the fram on the drivers side. Mine kept corroding up causing low fuel pressure. I ended up having to add another ground wire in addition.

I've replaced fuel relay, new wires going to pump, ground wire is brand new, bolted to frame with new bolt, where it is grounded is down to bare metal, replaced ground strap from fire wall to motor, new ground strap from frame to motor, new ground on battery, I,m getting 12 volts to fuel pump. This is my second new fuel pump, third new fuel pressure regulator. Any other ideals would be appreciated. Yes it holds pressure. When I replaced fuel regulator, before I put upper intake back on I hooked up fuel supply lines and took a pressure reading at rail, it was 61psi. Thought it was fixed, put upper intake back on and hooked everything back up then took another reading. To my suprise it was at 50 psi