hi. little bit of a problem with my 2005 citroen relay. 2.2 HDI engine. started cutting out when pulling up hill, or when it seems as though the engine is under more load than normal. engine management light comes on red and cuts out straight away. went into limp mode once but just cuts out mainly. 8 times out of ten it will fire up straight away afterwards, but now and then it will turn over but wont start, so will need leaving for 20 seconds or so. also ive noticed it only does it once the engines been running for 15 mins or so. today, I have heard a funny high pitched whinning/humming noise which runs on for around 2 seconds after the engine is turned off. like a pump run on or something. never heard it before. about 3 years ago I had fuel pump and injectors done. it has recently had a service I hope someone could shed some light on thuis for me I would be very grateful many thanks in advance