Can any one help my mutipla 1.9jtd was running ok but had the engine critical fault flash when i started it or drove over 80 mph and the glow plug light flashing. decided to check the glow plugs with the multi meter which showed one was not working but this was the one that I had just replaced. As soon as i had checked this i started the car and it is running rough like it is running on 3 cylinders. I checked and cleaned the injectors, i noticed that one was not working as when i removed the clip on the top of the injector the car was still running. does this mean the injector needs replacing. It is also limited to 3000 revs like it is in limp mode please help was suppose to be going away in a few days. Also are they suppose to have an engine managment light as no light comes up when I start the car.

You need to verify whether it's the injector not working or the wiring that's faulty.

Swap the duff injector with another, if the fault moves it's the injector, if the faults stays it's the wiring. If it turns out to be the injector, put the good injector back into it's original position - I believe the ECU has injector specific settings based on the codes on the injectors.