Can a FCD go bad?
 

I have an '87 TII with intake, downpipe, evc4 and fcd. The problems seems to be boost related around .45 bar. The car falls on her face. I've checked the install on the fcd and have tried different setting 2-12 on the dial, hks is the mfg of fcd. Can I test the fcd to see if it's bad? Or is there something that I missed in the install, is there something to disconnect?