I ran across this thread and I am having a similar problem. My engine idles smooth and sounds normal. If I give it any accelerator at all it blows black smoke, even at minimum acceleration. It will accelerate to about 55 mph, but then starts to shake some and has trouble accelerating past 65. It has a knock starting around 2k rpm. I have checked the turbo (no play in shaft, spools fine), the vacuum system, the cac hoses and changed the map sensor. I noticed the oil looked and smelled burnt even though the oil only had a few hundred miles on it, so I changed the oil. Oil already smells burned again after about a half hour of run time. I think I have gained a half quart on my oil dipstick in half hour of run time and 2 weeks of sitting; but I can't be certain the oil didn't just settle out a little high on the dipstick after the last oil change. I am thinking that the problem is likely a leaking injector, but I am not sure how to test this. Any suggestions?
I appreciate any help I can get, the Libby has been sitting for about 3 weeks with this problem, and I really need it back on the road