Leaking injector seals can certainly cause this problem. The parts are not expensive,but it is a massive job and you run the risk of breaking or damaging other parts in the process.Is it worth it on a car this old?

I had a Citroen C3 with this engine and blown injector seals are usually accompanied by a very noticable chuffing noise with a smell of diesel exhaust in the cabin. Didn't have any problems with juddering or misfiring until later when I had air getting into the fuel system and also having to give the priming pump a few squeezes to get it started. Replacement of the fuel filter, its housing and adjacent pipework cured that.

I've had it on my 1.4Tdci, and it's always down to injectors and the associated pipework. Luckily, I've never heard of anyone having trouble getting the injectors out of this engine (where as Mercedes vans are often written off because the injectors won't come out). I've had new seats and seals and pipes three times on my 2006 Fiesta, in its 217,500 miles that it's done.