External wastegate problem....
 

ok i finished my big turbo setup now heres the case when i had just installed the wastegate would spike 15psi and drop down to 10psi and stay there now i went to the local hangouts to race but as soon as i punched it spiked 10 psi and went down to 5 psi and stayed there any ideas??? should i hook up the boost controller or.... let me know thanks
TwEaK