If this problem hasn't been fixed yet, I suggest swapping out your throttle position sensor. My 09' SCG had the same issue. Didn't throw any codes either. I ended up findin someone with the same issue in YouTube and they had a throttle position sensor that was on the way out that didn't throw any codes. I replaced my throttle position sensor myself and problem solved. I have the EBR ECM with Jardine exhaust.