Prolonged crank - 2007 4.0 v6 EB

[Explorer_PL]

Our 2007 EB with 127k miles, 4.0 v6 has that long crank symptom that I think it's getting worse.
No codes, never failed to start, new spark plug and wires (Motorcraft).
Did anybody pinpoint the actual solution to that ? I know many of the 4.0s suffer from that.
Probably new fuel filter would not hurt. Is there a some type of fuel back pressure/return valve that allows the fuel to drain back and then it needs to be brought back to the fuel rails after a night ?
Thanks in advance

 

[Gorb]

I'd throw a coil pack at it and see if that helps. Usually that gets replaced along with the plugs and wires. Even the motorcraft one is fairly inexpensive.

I was starting to have this problem but after I changed the coil plugs and wires it went away.

 

[Tech By Trade]

Its funny, I was running into the same issue. I was thinking my fuel pump was on the way out, or it was losing prime some how. It was especially when it got colder out. Since I changed my MAF sensor and cleaned up all the wires that were missing their sheathing it has started without issue. I didn't really notice until I read this, but it may be worth a look.

 

[Explorer_PL]

Thanks, will look into wires, and the coil pack is on its way.
I was cleaning my TB on the v8, and some of the wires are in such a bad shape. I had to fix the passenger side cam sensor since it was a bare with no insulation.
But after all, the 06 is over 13 years old.