I just picked up a 2006 KR in the rustish brown color (anyone know the correct name?). It's got 67k miles. All I can say so far is, wow. I'm very impressed with the truck.
My 2nd day driving it I experienced a pretty nasty rough idle for about 20 seconds. (since google is my friend) I'm thinking this could be a spark plug or coil pack problem. Does that sound correct? I'll post some pictures tomorrow after I take it back to the dealer for them to do a final detailing.

Are the spark plug problems the only known issue with these years 5.4s?

 

I think the color is Copper. be sure to post pics. The rough idle could be a few things but more than likely a COP. Maybe get the dealer to check them out when you take it back?

 

I plan on having them double check everything while looking for the cause and, if they didn't already do it, do a full tune up. My KR was sold "Certified Used" from a newer Ford dealer but I let the finance guy talk me into the extra warranty (I've never bought one before) so I've got a clean 2 years to keep bringing it back if they don't make it right.
Knock on wood, I don't think it will be a problem.

 

Still holding off on taking pictures. Dealer still hasn't done the "detailing" they promised me. I spent all last week zipping around in a Ford Edge because the dealer was trying to find my idle problem. I finally went in on Friday to "show" them the problem since they could not reproduce it. Looks like my 5.4 needs a new cam phazer on one bank.

 

I got my truck back on Friday but by Saturday it had repeated the rough idle. Sunday it did it long enough to throw a check engine light. Truck went back to the Ford dealer on Monday. 1.5 months I've had it and 2+ weeks it's been in the shop.... this is not instilling confidence

 

Hate to hear that slo... best of luck getting everything straightened out.

 

Called the service writer, he said they discovered "Too much end play in the crankshaft", now I wait while they decide if that can be "fixed" or if they will drop a reman'd engine in it. Obviously my vote is for the reman as I don't see any sort of LEGIT way for them to fix "too much end play" without getting really creative. Not to mention the idle noise/problem that was seen as a cam phazer malfunction was probably a low oil pressure problem all along, so do I really want to drive away with an engine that ran around for WHO KNOWS HOW LONG with low oil pressure?

 

New/Factory "rebuilt" engine installed. Truck came back to me on Friday. Crossing my fingers there are no other problems.