What grade of oil are you using ? You must use 0w30 otherwise the oil is too thick for the oil pump on the fuel system to feed the injectors correctly. If you are on the correct oil grade, it's probalby the oil rail pressure sensor playing up. This has to be done at a dealer as it has to be coded when installed. Don't let anyone tell you otherwise. Put a reply on if the oil grade is corect.
DL, December 2008