Hard Start rough idle when cold

[BlackDevil]

Truck been running like a top...changed plugs and wires last weekend with Motorcraft plugs and Autolite wire set. Just regular maintenance. A lot quicker start ups since.

Came home from work last night parked the truck sat overnight and this morning she would start but was spitting and sputtering and would stall out unless I gave it gas.

I'm like wtf! let off the gas to put it in drive and she stalls. Start it back up she's running like shit again so I held the pedal about half way dropped into drive it chirped the tires and off I went.

Got to the stop sign about 4 miles up the road and she's purring like a kitten.

On break after it cooled down same thing running like shit.

Leaving work with cold engine same thing, running like shit.

So in conclusion when it's cold it doesn't want to run right but once the engine warms up for a few minutes it runs perfect.

What the hell is going on? My father in law said I need to change the IAC valve but he's a Chevy man.

I'll put the scan tool on tomorrow just didn't have the time this evening.

Any help would be GREATLY appreciated!

 

[Sunk]

Try cleaning the IAC valve before you change it, that may help.

Mine's been doing this for probably 50k, no clue what it is.

 

[BlackDevil]

Good idea...I'll take it off tomorrow and clean it up good with carb cleaner first cuz the Motorcraft IAC isn't cheap.

 

[Earl43P]

I'll bet it's fuel pressure dropping off.

Prime it before cold-starting by turning the key to Run, do not crank the starter.
Key back to Off, repeat, repeat, then crank it over.