dash 8 problems

my dash 8-100 that i got to make the AI flyable is having a problem during flight and takeoff. This is wht happens the engines after i throttle up past 50% N1 starts surging like this: when i firewall the engines to 100% N1 its surges up to 127% N1 then drops down to 100% N1 and i can only speed up until 80 knots and it wont go faster any help and if it is dealing with the cfg how do i change it cause im not on my computer with fsx until july 27 soooo im done :exclamation