Hello and welcome to Just Answer!
The problem may be with the fuel pressure regulator located on the fuel rail. I have replaced many on the Northstar engine. Inspect the regulator by first removing the
engine cover. Then remove the vacuum line that plugs onto the fuel pressure regulator.
Inspect for fuel comming out of the vacuum line. If there is fuel in this vacuum line, then the rubber diaphram located in the regulator is split and excess fuel is being sucked into the intake through this line. This will also explain the hard start. If the regulator is faulty, the fuel rail pressure will bleed off when the pump is not running causing a hard start condition. Replacement of the regulator is pretty easy. Remove the retaining clip that holds the regulator in place. remove the old regulator and make sure all o-ring seals are
also removed. The install the new regulator. Good luck and please let me know what you find. Thanks!
I will take more fuel to start the engine during colder temps and when the fuel pressure and fuel volumn isn't present, it makes for a harder start when cold.