Car wont show boost till 30 percent throttle or above, more throttle more boost, so if your seeing 1-2 bars @ 30percent id think thats normal. If your seeing 1-2 bars 100 percent throttle at 5K rpms then you have a issue. Id suspect the BBV,Map would be the issue. It would take a Huge vacuum leak to bleed boost. If you start your car and it sounds like a Huge cam Ls1 then maybe its a vac leak issue lol