I'm having similar problems but mine won't start at all:
I have a 2004 Getz 1.5 CRDi (3 Cylinder engine) with about 115000km on the clock. About a two weeks ago it wouldn't start, so we towed it in to the dealers. After running the diagnostic check they announced the rail pressure sensor needed replacing. They quoted me R9000 for a new one - nearly 13% of the price I'd paid for the car!!! I sourced a Bosch replacement at about R1700 and they have now fitted it to the car. It still won't start.
I am now waiting for the latest feedback from the dealer but I've lost confidence in the reliability of their diagnostic process - what if their diagnostic machine says I need a different part at a similar price again? I can't just keep on paying -imagine I'd taken their R9000 part?? Do you have any experience like this?