I was at Daytona this past weekend running my 3.8 Camaro.
It ran perfect for the first three sessions on Saturday, but on the second to last session on Sunday it was way down on power at times, and the CEL light flashed. The only code in the PCm was P0300. In reviewing the logs the times when it was down on power and the CEL flashed it was maxed out KR.
Here is a log from Saturday (Daytona5) when it was running great and Sunday(Daytona7) when the issue started. Also, the current PCM tune.
Dayton5.hplDaytona7.hpl110114rcomps.hpt
I checked the engine over and can't find anything mechanically wrong with it.