Lepprykaun

I've owned my 93 RX-7 for about a month now and have been slowly working on it to get it in good enough shape to pass an out of province inspection. Just the other day i noticed that my boost gauge likes to "flutter" at idle... it doesn't just sit there it flutters a little bit, and recently i took it for a spin and instead of getting 10 lbs of boost i only got 8 lbs and it took awhile to get to 8 lbs. normally by 2500 rpm im at full boost but now at like 3000 rpm im only at 8 lbs and won't go higher. after my little test drive i parked it in my garage and was letting it idle for a bit; i gave it some gas and as i did white smoke came heavily out of the exhaust... which was the first time it's ever done so... So what i'm trying to say/ask is, What could be causing the white smoke and why am i not hitting full boost? i also noticed that i might have a small vacuum leak, which i cannot find. could that be causing my boost problems? and possibly even the smoke? i wouldn't be surprised if a vacuum leak was the problem of my boost but... white smoke? Any opinions and or comments would be appreciated