You need to have the valve train looked at some have had the roller bearing go bad and it can damage the engine. If your comfortable working on your own car there are youtube videos on this. Fordteckmakuloco is highly recommended on you tube watch his videos.I have a v6, early model I got in Nov. 05, and when cruising i get an intermittent vibration noise or ticking noise @ 1500 rpm's, it disappears if i accelerate or let off the gas.
It happens when the engine is cold and warm, will be fine all day and then start happening for about 20 minutes then disappear for 3 or 4 days.
My Ford dealer had the car for 3 days and could not duplicate the trouble.
I have the most recent flash upgrade and have checked in and around the engine compartment and not able to find forign objects.
Any help on this would be great thanks!!