Hi, I have a 2008 diesel Ford Fiesta Zetec which I've had issues with since I bought it last May. It tends to sporadically chug or shudder. 3 times now it has shuddered to the point of slowing to a halt with 'Emergency Malfunction Service Now' coming up on the display. The first time this happened I drove it home slowly and brought it to the garage asap. The second time was a case of switching the car off and on again, and the emergency warning disappeared. The third and most recent time, it wouldn't go past 2000 revs or 20mph, turns out the 3rd injector was gone. I've brought it to the garage maybe 6-7 times since last July, 3 separate mechanics - not one of them knows what's wrong with the car. They've run diagnostics plenty of times, there was a sensor in the engine that was also replaced (fuel sensor I think?), and all filters changed. I'm still none the wiser and the shuddering happens on a regular basis, no matter what speed. Can be driving on motorway at high speed and it'll just jerk/shudder, then again a couple minutes later. I've tried driving slower, makes no difference. It's gotten to a point where I can't depend on the car for long journeys. Any idea what this might be? The car was last fully serviced in July 2021 at 232,102km, the clock now reads 239,343km. The car is spotless. When you lift the bonnet, you'd think it was brand new, same can be said for outside and interior. Full service history. The only problem the last owner had was a fuel injector, the 3rd one, which is the one that was replaced a couple months ago.