Ok so here is what happened.....I went to install my Hallman's MBC yesterday. After i completed it, I took here out for a test and tune. After a while i realized i was boosting around 17 - 18 psi when i only wanted 15 psi. So After finally getting it down to 15 psi, I took her for a spin on the highway. When i got back home, once i let off the gas the car just died. That become the story of the day...and then all the sudden i throw a CEL. The code that came up is P1400. Now after speaking to a fellow DSMer, I adjusted my BISS and now the car idle seems to be fine, but i am still getting this CEL. My question is, are these two issues related? I honestly think i have a vacuum leak as every now and then i get rough idle still. This leads me to believe that the issues are not related but i know nothing at all. I also wnat to know, if these problems can be the result of the short term overboosting that went on yesterday?HEre is a list of my few mods:

LICP
UCIP
HKS SSQV BOV
Intake Filter
Boost Gauge
Air/Fuel Guage

Everything else is stock. Any and all help on this matter is greatly appreciated. With me guessing, I am assuming i did some damage to either the TB or manifold itself since the MDPS (not sure of the acronym) went bad at the same time as this problem.

Jerrome