Well for a start regarding your fault code. This is what has come up for me on the Delphi system.
P0246 - Turbocharger (TC) wastegate regulating Valve A - Circuit High
Possible cause - Wiring short to postive, TC wastegate regulating valve, ECM.
OR
16630 - Solenoid Valve for Boost Pressure Control (N75): Short to Plus
P0246 - 35-10 - - - Intermittent
The actual name for that part is the turbo charger wastegate solenoid or also known as the N75 valve. Hope this helps.