I'd like to share with you the symptoms hoping that a knowledgeable and helpful soul might direct me how to diagnose the problem.
There is a slight rattle, especially at idle (as if you pass your fingers over wheel spokes), which wasn't there before. I've read this could be wastegate noise. In addition, when I drive the car, it makes a guttural sound and there is a loss of power. If I floor it, the computer displays the half-engine icon and puts it in limp mode. Before the car goes into limp mode, I hooked up my AccessPort and measured a maximum of 6.8 psi of boost, while I normally get about 13.5 psi (with Cobb v4.01 sport map). Is the measured boost the combined value of both turbochargers? If so, then getting 6.8 psi might mean that only one turbo is producing boost? Accessport reports engine code P30FF (boost leak from pressure line of turbocharger 2).
So what could it be? Is the wastegate stuck open? Is it the wastegate actuator?
Thanks in advance!