i got a 6 liter with 107k and it hesitates badly and stumbles with hugh amounts of white smoke coming out of the exhaust followed by black smoke as it clears out, what is the problem? any help much appreciated...

 

Be More specific... Does it do it on startup? or during the time ur driving it? If it is on startup, it sounds like you need to take it to the dealer and have them Re-program your cpu chip. I had to do that to mine after about 30,000 miles. They also had to replace a few injectors because it did it so bad. And if it is doing it while ur driving it, then it "could" possibly be your throttle plate. but there are numerous things it could be... EGR, INJECTORS, CPU-CHIP, THROTTLE PLATE... etc...