I have a ford focus 1.8 tdci 2009. After a couple of weeks of buying it the car started to judder. It would do this anything between 1500 - 2000 revs, once I increased revs it would go back to normal. I took the car back and they plugged it into their computer and updated the PCM computer. This did nothing for the car. I read that it could be the EGR Valve and to put a blanking plate on. I did this and for 2 weeks the car ran fine but now its back to hesitating/juddering. Sometimes it struggles to start also.