Search for Surfblau's post: "300TD Hot Idle Shaking - apparently solved" for a list of common places to start resolving this problem. I'm having a similar problem and am going to start with Diesel Purge, which seems to be what everyone is recommending. Then the governer screw/rack damper screw. Sometimes BioD will run smoother in my case and might be worth a shot for you...not sure why, but someone on this post prob does. It could be bad compression too...I think compression should be about 150 and if it's less than 75% of that it will make the engine shake excessively.