Help cold start problem

[VirtualExplorer]

1991 ex 4 door 4.0 v6 5 speed

I have been fighting with this problem now for about 2 months i just can't figure it out? When the truck is warm it starts up great, but when it's cold it takes a while to start.
the first thing in the morning the truck just keeps turning over intill it starts usally about 15 sec cranking
i have replaced the ECT sensor
fuel pump and filter
fuel regulator
changed the oil to thinner oil
added some slick 50
plugs
MAS
cleaned the IAC
new radiator
new starter

nothing i do to this truck helped the problem.
I got tons of parts for this truck so any suggestions to fixing this nightmare will help......

Thank

 

[MrShorty]

What's the fuel pressure doing when it has trouble starting?

 

[marragtop]

Will it start if you turn the key on/off a couple of times before cranking in?