91 300d still poor boost problem

[Mwasmuth]

1991 300d 200700 on the clock I have no codes cleaned fuel system with bio and diesel purge made a great improvement, with direct vacuum to waste gate I can boost over 15 20 psi no problem installed new vacuum switch for waste gate and will not boost over 7 psi or so with old switch installed would not boost 4 psi. It does boost up faster now but it seems that the computer is requesting the waste gate to be opened. Boy I wish my 3000 OTC scan tool could watch data stream on this so I could see what the computer was thinking. Either way It don’t and I can’t. I have not codes and good vacuum everywhere. Any ideas thanks for your help.