Tabes

Hi there, I am running a 55 plate 1.9TDI Galaxy 130bhp. Over the past coupld of months I have been getting problems starting, 90% of the time it is O.K but then at times it takes several attempts. I have also experienced the engine cutting out completely whilst driving, I stop and restart the engine and all is O.K again. It also has cut out dead whilts ticking over a few times. Any ideas what the problem may be?? Help!!! Paul