I had the same problem, your idle speed is too low! The oil pump is not turning fast enough when you are at idle. What happens is your engine reaches operating tempature, the oil is hot and thins out, less oil pressure. An idle speed of 500 rpm is too low and the oil pump is not pumping as fast, oil pressure light starts to flicker.
You need to increase your idle speed wich can be done with software. I did not replace my ICV I used a Vedis scan tool to increase the idle speed. Take it back to the dealer and have them make idle speed adjustments.