Boost control problem

[Blue95GST]

ok, before i installed the joe p mbc, stock held boost right around 14, now with the mbc installed and turned all the way down, boost spikes 20-23psi and settles around 16...any ideas?

 

[Blue95GST]

car came with ported t28, oem rebuilt motor with about 30k on it, but no other supporting mods for anything past stock, since i'v replaced everything else maintenance wise, got intake, 1g bov, full 3in exhaust, safc for tuning, boost guage, mbc, and now looking for fp, injectors, and logger to take advantage of the t28