My vectra c 150 bhp 1.9cdti started getting jerky, if it was a petrol you would say it was misfiring it also cut out completely with no warning or spanners showing on dash.
After reading various threads I changed the no.3 injector electrical connector this cured the " misfiring" but the car still cut with no warning, I disconnected every electrical connector I could find and cleaned them with swich cleaner, this made no difference,I then stripped and cleaned the EGR valve it was well and truly coaked up,still no improvement it still cut out.
Getting desperate now I stripped and cleaned the electrical part of the accelerator pedal, still cutting out, really desperate now I decided to change the throttle body, so purchased a good used one from Vauxcentre with 6 month warranty. Stripping out old unit no problem but trying to clean the oily crud from the inlet manifold was difficult, I used a bottle cleaning brush.

Eureka now covered over 200 miles with no problems.

Brian

p.s I just hope I am not shouting too soon.