Fuel Injector problems of the 2008 Lexus LS460

When starting my 2008 Lexus LS 460l, the vehicle starts and immediately shuts down (stalls). This usually happens when the vehicle has been sitting for long periods of time; e. G. , overnight, 9 hrs at work. On may 30, 2010, after sitting overnight, the vehicle started up fine for a trip to the grocery store. Fifteen minutes later, I returned to the vehicle, started the vehicle, and it immediately shut down. The vehicle was repaired by Lexus of rockville on may 20, 2010, but as of may 30, 2010, the problem continues to persist. Lexus of rockville replaced all fuel injector assemblies.