i was driving to work the other day and everything was running fine. right before i pull in to work, a white gsx pulls up next to me and we run em, and i hit 20-25psi or so. i pulled into work, parked the car and shut it off. about two hours later, i tried to leave to get some lunch, and the car was extremely hesitant to start. the rpms would hover around 500 for a few seconds, then die out. when i pressed on the gas, the fuel response was really laggy, and as soon as the boost gauge hit 0psi, it would sound like a misfire or timing off. on the vpc, i had the crank the fuel up like 200% of what i usually drive with just to get it home. i was able to get into about 5psi of boost, but very roughly. during the ride home, i tried to turn down the fuel, but it just kept stalling out. anyone have any ideas?

so far:
changed the spark plugs
checked for vacuum leaks
ran obd II scan (no codes)
radiator flush - not pertaining to the problem, but needed to be done
tightened down all nuts and bolts, etc.