I have a 1999 Escort Van 1.8 diesel (non turbo) which has been playing up. Basically it stutters a bit when driving. I can compare it a bit to when i HT lead is on its way out on a petrol engine. Something holds it back for a second, then it goes again. Other times it still drives ok but feels a little underpowered. This is alot more noticable when cold but doesn't completely disappear once warm

I've changed the fuel filter and injector crossover pipes, as well as running injector cleaner through it.