Acceleration problem

[Iamtony]

Hi people. Need a bit of help. I have a 2004 caravelle 1.9 tdi with 200000 on the clock. It has developed over the last 10,000 miles a problem. When I accelerate the whole van vibrated quite badly between about 1500-2500rpm. When I keep the speed constant it's ok. Some times it gets very bad and I have no power to accelerate and all I get are vibrations and the it feels like i'm in the wrong gear or something, but if I shut down and start up again all seems ok. Hoping this is a common problem someone can help me with!
Thanks for any replies!

Tony

[Iamtony]

Rgot to mention it also smokes alot during acceleration only noticable at night with light behind me.