99 Explorer Sport 4.0 SOHC Starting Problems

This problem first happened about this time of year last year when it got cold here in Chicago.
It was fine all spring, summer, and fall and now its back again.

I try to start it and it either fires right up (about 66% of the time) or wont.

When it wont start it might sort of fire for 1/2 a second (what I call belch start) then just cranks away with no sign of firing at all. It does not seem to matter if it is stone cold or if it has sat for a few minutes while i'm in a store. Problem will pop up either way for about 1/3 of my start attempts in this wonderful chicago winter weather.

When it's not starting it's cranking fine and I dont smell gas at the tailpipe.
When its cranking it is giving no signs of firing at all. Just like there was no spark or no gas what so ever.
I don't let it crank to long, I'm not a fan of cranking over 10 seconds. (insert your own joke here)

I have found that if I shut it off for about 20 seconds and turn it to on and wait for the humming to stop (i think that hummimg is the fuel pump pressurizing???) then try to start it is my best chance to get it going.
Sometimes it will take me about 5 to 10 of these attempt cycles to get it going.

I still have my original battery (6+ years now) but the cranking speed seems fine. I'm wondering if the starter might be taking all the battery has and not leaving enough juice to fire the injectors or supply a good spark. It seems that if that was the problem and it started a year ago the battery would have died by now though.

My explorer will sit for several days where I dont run it and I was wondering if this had anything to do with it (maybe relay contacts are tarnishing or something like that).

So to recap this strange problem;
Cold weather (around freezing or below). Engine cold or warm. Either starts right up (66% of time) or cranks good but does not fire up. When it does not fire up it may "belch start" for about 1/2 second then just crank away with no sign of spark or fuel or both.

 

One other thing. I just remembered that when the problem first started last year about this time of year I heard a strange sound one day.

It was like some pressurized air let loose all of the sudden.

It was a loud "PFEW" sound that sort of sounded like it came from the drivers side of the engine compatrment.
It lasted only 1 second at most and the truck seemed fine but I think it was shortly after that when this problem started.

I was not even sure if it was my explorer that made the sound or not but now looking back on it maybe it was and has something to do with this problem.

 

Have you ever pulled the fuel filter an dumped out the contents to see what it looks like ,, like maybe water in the fuel ?

 

Have you ever pulled the fuel filter an dumped out the contents to see what it looks like ,, like maybe water in the fuel ?