I have a Citroen HDi 2 litre plate RY53 , yesterday on the M4 the engine suddenly lost ALL power ( not limp home ) but no noise/clanking etc and only lights that came on were yellow engine management and the circular dot red light at the right end of water temp, I got it to hard shoulder and it died. After 5 mins I turned it over , it started but would not rev at all then stopped. Then since then wont start but will turn over. AA looked at it and oil ok, hydraulics ok, water ok – no oil in it or overhot or low or anything) – could not see what wrong. Cambelt was serviced at 90,000 , car now on around 120,000. Plus with no noise he did not think cambelt but some sensor ?? any help most appreciated