5.4L E350 Cold start issue

!997 E350 5.4L 124k miles. Purchased van Oct. 2015 and am doing service interval maintenance b/c previous owner remembers nothing and I want to get this ready for summer family travel. Searched forums but all threads are about hard or no start conditions.

Approx. 3 month after purchase I noticed cold start issue. Hot starts are no problem.
After sitting overnight engine will crank and catch - then almost dies BUT NEVER DOES DIE - then catch and run fine. This happens almost 99% of the time. It very rarely needs a second crank.

Engine was way past due for plugs so here's whats been done and checked:

plugs replaced w OEM motorcraft
boots replaced
injectors sent off for cleaning and R&R. All within spec electrically and mechanically. None leaking.
Fuel filter replaced - OEM motorcraft

Issue persists after this service.

My first thought was fuel pump which has NOT been serviced. I believe specs are 38psi KOEO and 28-45psi KOER
Fuel pressure checked KOEO - 38 PSI, KOER - 33psi (this seems a little low although I am using a cheapie gage)

regulator seems fine - disconnect and pressure rises, add vacuum from hand pump pressure decreases
no gas in regulator vac line
Pressure held overnight from 38 to 20 psi
wide open throttle pressure rises to 40psi then falls back down.
While driving pressure seems around 33-40psi depending on loads
When I first connected fuel pressure gage I thought it went to 10psi then cycled key and went to 38psi but that may have been rail and injectors filling after being off the vehicle. Will check it again tonight.

My next guess is IAC or ISC valve. I've tried to give as much info as possible. Other than that the new plugs and refurbed injectors have plenty of oomph and it idles and runs fine.
Any thoughts?
Thanks

Additional :: No codes being set. Also hard cold start is somewhat misleading. A better way to say it is this happens after sitting overnight which here in the southwest is not really cold.

Some times the check valve in the fuel pump will leak slightly bleeding fuel back into the fuel tank. Install the pressure gauge in the evening. Look at the pressure before starting in the morning.
http://www.tooltopia.com/ sells inline check valves. Search check valve.
Otherwise check relays or camshaft sensor if no spark in the morning.

As is the case sometimes there may be several things going on simultaneously. Posted a thread a while back in Cars in General about electrical grounds that seems to have helped quite a bit although this problem rears its head occasionally on this vehicle.

After locating, cleaning and snugging up grounds on this van and two other vehicles my cold morning starts are definitely no longer a problem on a Chevy truck and Buick although the van problem shows up very rarely now and again.

I have since replaced all coils w/Motorcraft and the uphill misfire in high gear low rpm is now gone.Will check your suggestion.

Thanks

Had a very similar problem with a 1995 351w e350. Hard or no starting when it was wet or cold outside. Ended up being the ignition coil... looked fine but when I changed it she started right up.