jt_cummins, I have good news and bad news for you. The good news, you are not the only one with this exact issue. My 2010 G56 does the same exact thing. I'm running EFI Live by MotorOps and an Insight CTS2, and I have the same exact issue as well as a P2579 mil that I can't get rid of. I've replaced MAP Sensor and Turbo Speed Sensor with no fix. I sent the CTS2 back to Edge and they put it thru all kinds of tests and couldn't find anything. The 2 weeks without the cts2 out of the truck i had the same results. I can hear the turbo spool up so i know it's spinning. If the cts2 shows any boost while driving the EB will slide you in the seat. If no boost reading, its there but probably reduced by half. MotorOps has basically washed their hands of it saying it must be a wiring issue with my truck. I've checked it all, cleaned connections, checked grounds and nothing. Who is your tuner? If it is by chance MotorOps we would maybe have something narrowed down. If not I will just continue to beat my head against the wall. I guess I didn't say what the bad news was but it's basically that I haven't figured anything out.