I've got a 99 f-150, 4.6 l motor, 100k miles, recent tuneup.

On cold mornings the engine does not like to start on all cylinders for a few seconds. Not a huge problem, but enough of one to prevent me from using my remote starter (motor stalls). Otherwise the truck runs great.
Suggestions?

 

If you didn't mention recent tuneup, I would think IAC. Has it been acting up since the tuneup? Do you notice a little black smoke from the exhaust while it's doing this? To find out if it's the IAC, open the hood, and remote start it. As soon as it fires, and if it acts up, rap the IAC or TB area with a ratchet or something. If it immediately straightens out, that could be your answer. I just realized, I don't know where the IAC is on a 4.6, This is where someone else steps in to help.

 

The cold start problem was there prior to the tuneup, and stayed the same after. I have never noticed any smoke at any time.

My main problem is that I'm an old fart who thinks fuel/air mix should be adjusted with a screwdriver, not a computer. Hell, I couldn't even dial 911 on my phone cause I couldn't find the eleven.

 

Seems like it needs to be leaned out at start up? If so, I'd remove and clean the IAC valve with carb and choke cleaner (high pressure kerosene). I did this a few days before my wedding in August of '04. Been super since, not one occurance of the "stuck choke sydrome". I sprayed stuff in there, worked the valve back and forth, spraying it everytime I moved it. Let it drip dry a while, put it together and that was the end of it. Like I said, I don't know where it is on the 4.6.

 

Another thing you can do is clean off the MAF sensor with some carb cleaner. Its the alumunimum sensor pod up where your air filter is. You may have some buildup or debris on it that is throwing off the mixture. Just don't try to touch the wires or anything inside. They are delicate.

Once that is cleand of, disconnect the negative post on the battery for a couple of hours. That'll reset the computer. The truck might run "funny" for a couple of days until the computer relearns your driving habits.

I had a very similar problem on my 4.6 Grand Marquis. I did the above and it came out of it.

 

If the EGR is sticking open it will cause very rough starts as well.