Nissan Repair: Cold Start Issue, fuel pressure regulator, sr20de engine

Question
Hi,
I've been having some problem with my 1996 Nissan Sentra/ Pulsar (SR20DE engine).  The issue at hand is that I am having a hard time when starting the car when it is cold.  When I turn the key, the engine will just crank and crank and crank but unfortunately it will not pick up unless I step on the throttle to about half way and only then the engine will start.  The odd thing is that when the engine is warm and and you turn it off and immediately on again it will start without any issues and without you needing to step on the throttle.  I have eliminated the obvious stuff such as O2 sensor, temperature sensor, spark plugs, alternator, battery, fuel filter and using 98 Octane fuel.  I was hoping you can shed some light as to when I can go from here and fix this intermittent problem.  Thanks for all your help in advance.

Answer
Mervin,

Sounds like it is getting too much gas and as a result the cold engine needs more air to compensate.  I would be looking at fuel pressure and any possible fuel leaking into the combustion chambers.  Check each plug for ones that are really black.  If you find one you have found the leaky injector.  Also, the fuel pressure regulator could be blown causing too much gas when cold.