I have a 1997 Ducato 1.9TD campervan which has done 113000 miles. I've only owned it a short time, but have found that it has a problem at particular revs e.g 8mph in 2nd, 30 mph in 4th etc. It feels like someone is kicking the accelerator and it's quite an unpleasant surging/juddering feeling. The only way to stop it is to change down or to accelerate so it's quite hard work to drive in traffic. The initial thought was that it was my fault letting the diesel engine reach too low revs - well that isn't true as you have to rev the guts out of it to get past this problem in each gear. It's been suggested to me that this could be a worn fuel injector pump - cost to rebuild £1200 or new £2000! I'm told that this problem is one affecting earlier diesels now that the diesel fuel no longer has any lubricant in it. Is all this likely, and has anyone else had this problem?