Chad,
The black smoke, you are seeing, is probably from overfueling at low rpms. Since the turbo hasn't "spooled-up" & started pumping enough air into the engine to compliment the amount of fuel the engine is getting. The result is unburned fuel, which, comes out the tail pipe as black smoke.
Regarding the carbon build-up, that can happen. I had the problem with my '03.
What I noticed was a "knocking" sound, at lower rpm's (idle to 1400). It sounded like one cylinder was out of an early Cummins engine. Had the diesel "rattle" out of one cylinder.
I took the truck to the dealer, a number of times, complaining of the knock. The first time, they could not duplicate the problem. Later, I learned that it happened when you put a load on the engine. By load, I mean, just letting out the clutch til it just started to engage. The engine would notice the load being put on it & it would start knocking. After 1400 rpms, it went away.
The Dealer acknowledged the "knocking" after I repeatedly showed it to them. However, DC would do nothing about it.
I read here, about a member that had the same issue. Industrial Injection pulled the injectors & noticed a carbon build-up on the injector tips. They figured that was what was causing the knocking. It was suggested that using an additive, that included injector cleaner, was probably the answer.
The other answer was working the engine very hard & burning the carbon build-up off. Since most of us don't work these engines as hard as they were probably designed to run, the additive seemed to be the best answer, to me.
I bought some Primrose Power Master 405 additive & put it in the fuel. It took quite awhile & a trip, towing my trailer, to CA, to clean up the injectors. The knocking was gone when I got to CA. Worked the engine, fairly hard, towing uphill.
The knocking came back, for a very short period of time, right after getting back home in Phoenix. However, it has not returned, at all, since then. That was last November '05.
I chose Primrose because one 12 oz. bottle treats 187 gals. of fuel. It's highly concentrated stuff & seems to work, for me. On the bottle it says: Raises Cetane Rating, Quicker Ignition, Cleans Injectors, Lubricates Fuel Pump, Lowers Starting Temperature, Reduces Misfiring.
I was mostly interested in the injector cleaning & the added lubricity. The rest of it's qualitys are just a plus.
I've, also, added a bit of Marvel Mystery Oil, just for a bit more lubricity. The recommended dosage is 4 oz. to 10 gals. of fuel. I do about 2 or 3 oz. per 10 gals. , along with the Primrose.
In my opinion, adding extra lubricity, especially to the new ULSD may be a good idea. Many people think that the new fuels do not have enough lubricity, added at the refinery. Adding a little, yourself, will help insure that your fuel delivery system gets enough.
I don't know anything about BG Products. I have heard the name, before, & as I recall, it was in a positive light. But, not enough to recommend them.
There are many additives, on the market, most of which are good. My understanding is that Stanadyne products are considered to be some of the best & even recommended by some diesel engine, fuel system manufacturers. I don't think you could go wrong with them, at all.
Don't let all this stuff scare you away from diesels. These engines are great. I think most people just drive the damn things & don't have many problems, at all. A lot of us, on the diesel sites, are fanatics about their trucks & engines. We "get into this stuff" more than the average person & notice every little change in sounds & driveability. However, some of the recommendations are pretty good & will help keep your engine running great for many miles.
Good Luck & enjoy your new truck.
Joe F. (Buffalo)
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