GMC Repair: fuel sender, chevy silverado, residual pressure

Question
I have a 2000 chevy silverado 2500 series 4wd pickup that has has become hard starting over the past few months.  The truck has 60000 miles on it.  The fuel sender has been replaced under warranty once 9-20-04 at 34000 miles. Also the fuel regulator was replaced under warranty at about 30000 miles.   A friend of mine is a heavy eq. mechanic and has helped me check the fuel sender pressure.  Initally after sitting for 8 hours we hooked up a pressure gauge and got a reading of 0 with no residual pressure.  When I turned on the key and started the engine the pressure went to 50, when I shut off the motor the pressure declined steadily to o or close to it.  Should there be any residual pressure when initally checking pressure?  Do you think that the fuel sender is bad again?   

                                          thanks Doug

Answer
Hi
Yes sounds like it.
I would check with the repair shop, and see if it is still under warranty.
It MAY be a warrantied part from GM/Delco, IF it was repalced at a dealership.
16k miles it should have lasted longer. Make some "noise"  if it is not warrantied, maybe they could help with the cost of repair or part.
I Hope this helps.
Good luck
Pawl