Since it is a direct injection engine some of the black may be from the valve stems. My truck does it, I ain't worried about it, runs good for now. When I start my engine I let it idle for a minute and go. I let it idle for a minute and shut it off. According to posters on this site the coolant still flows to the turbos after shut down. And I would think that oil flows to them also. They sit lower than some parts of the engine. CB

 

My truck is in the shop now for this very reason the dealer has ran codes and all sorts of test only to tell me that Ford has a TSB on it that states this is normal for a turbo vehicle they said it has to do with a cold start up and turbo warming time because the gas is being sprayed at such a high rate of pressue and delivery time that is doesn't have time to burn it off makes sense but sure makes the pipes dirty as hell. I guess this is something we owners are going to have to live with. in another topic is anyone having problems with a bumping or snap at stopping and starting like its coming off the rear end, they put new clutches in mine and changed the gear oil but its still doing the same thing?

 

Sounds like your describing a common issue with trucks period. I just had my 2011 f150 fixing for this problem. It's the driveshaft slip yoke where it's mated to transmission needs lube so it can slide back and forth when stopping and taking off. I've had this problem with every truck i've owned, Toyota, GM, Ford. Im super sensitive to this now so I amagine most people dont even thinks it's erritating. I think there's a TSB for it.