ca18det nistune timing problem car bogging

[mr_ca18det]

Been having this prob lately my car seems to fall on its face hard in between 3-4k hooked up the laptop and noticed my timing drops around 3500 - 3900 rpm from 11-12 degrees where i have it set in my timing map to 6-8 degrees. I used knock copy for the timing and knock map could this be a problem with my cas? thanks