Check engineering mode for throttle % when at idle. I'd have to look at mine to see what seems right.
Actually did that yesterday, it was behaving like it needs to and was at 5% throttle. Need to check what percentage it is when it misbehaves...i did get a CEL for throttle code
2009 G8 GT SRM, OBX Catless Long tube headers, DOD Delete, LS3 stock cam, tuned with HPTuners, Atari gauges.