Wandering boost

[TURBOV8R]

Running with a stock turbo,adj.actuator,and factory plumbing including the solenoid.Problem I'm having is I set the boost to 13#'spools quickly up to that point and if I hold my foot into it steady the boost drops and settles at 10#'s.Also running a TT chip if that could help any.Thanks!

 

[86Nick]

Could be a bad boost control solenoid or even wastegate actuator.