voltage drop at boost

[crazygn]

I hooked the turbo link up and checked my voltage at idle , its at 13 volts. But when the car is under boost it will hit about 3800 rpm and then seems if it wont hold any more rpm's and the knock gauge go's crazy , 2.* to 6* of knock the scan tool says. Thing is the voltage drops to 0.3 to 6.0 volts under boost at 3700-3800 rpm, this is when i get the bad knock and dies on power. Has any one ever had this problem before.

thanks guys