What oil did you put in it?
There was a TSB on the Duratec's about ticking. The TSB says after the car is warm and close to idling. The fix IIRC at the dealership is to remove the front cam and reinstall it and re-torquing the bolts in a certain fashion. I will try to find the link on TCCA.
I noticed in mine that if I used a heavier oil (like 10-30, I have a slow leak in the summer, so I was trying a slightly heavier weight oil) it makes the sound. If I use 5-20 it pretty much goes away.
Interesting. My wife has a 04 Escape that makes a ticking/rattle noise during a cold startup for about 20 seconds. Would this TSB fix that?