I was thinking turbo too, yes definitely the veins or possible vgt. But what i really think it is . When is the last time you changed the fuel filters? Bad diesel leaves a jelly the clogs em especially when its cold. I had a similar problem. Turbo needed to be cleaned it was 95 % better. Still got a under boost code. Then I changed the fuel filters and the truck runs like a whip.

Also i am know a Huge proponent to changing your thermostat at around 75,000. I think mine was stuck open a little. Cause now I am running a little hotter on the gauge. Burt when I look at the scanner 190 perfect. She likes 190

 

I'm not sure why people are trying to provide solutions to this. You're original post says 'no power or passing gear when I first start the truck up'.
It's a diesel and diesels don't put out power till they warm up. This is the way my truck has always run, since I picked it up new from Ford.
I've been trying to understand why my truck runs this way, since 2006, when I bought it new. So far, I found out that the truck does not operate at full power until it's warmed up because the computer has not yet transitioned to 'closed loop'. The computer runs on a fixed group of settings for the timing and quantity of fuel delivered until the sensors show that it's warmed up. Until it's actually warm, there's not much you can do to change how it runs.
If it coughs and sputters at idle or when your pulling away slowly that might indicate a problem, but to expect your truck to pull a boat out of the water after it is first started up is probably a bit too much to ask.
You can spend a lot of money trying to change this, but with all the money I spent on mine (and I've made quite a few changes), it still operates that way.
My advice would be to drive it a little easier till the water temp is up to the middle of the gauge. After eight years of trying to get rid of this behavior in my truck, I've accepted that's just ways it's going to be.
I don't mean to sound condescending...I really believe this.

After I've said all this, my truck runs much better cold, after I replaced my batteries. I just replaced them 2 weeks ago. I was noticing the voltage was dropping a bit even after it was warmed up and cruising on the highway. I watched this behavior for a few weeks but eventually it didn't start on a very cold morning.

 

One reason they like hot is diesel combustion requires higher heat. More than gas. Just think a thermostat stuck open will prevent it from truly warming up. Mine is running like a champ after I changed my thermostat. The exhaust even smells different . Go figure.

Just trying to help, as we all know who own a 6.0. That codes aren't always an exact science to what the problem is . You have to be a detective and find out a lot of variables. Just trying to help and thought that what these forums were about, sharing ideas.

In the end I would say maintenance , maintenance, maintenance. Also good diesel , if you have gotten away with crap so be it. Also the blu spring update if you rate doing any work and a coolant filter.