boost problems?

[pontiacgt500]

hey guys, recently ive been replacing vac lines and tees on my 98 gtp and i noticed when i was out a did a 1st gear wot pull and i was only reading 5-6 bars on the dic display and from what ive read its supposed to be all bars on wot. i unhooked the boost bypass solenoid too see if that was it because i know people bypass it aand there was no change it was the same smh and i just replaced the bypass actuator because of a broken barb on one end of it so now im at a loss on what to check and or replace next? any advice or anything would be appreciated thanks alot!

[Fivefingerdeathpunch]

Getting an actual gauge to read boost is better than trusting a lego brick on the dash.

Either get a real boost gauge or a scan tool that can read MAP KPA. You'll want to see a MAP KPA of around 150 for 7lb of boost, which is close to factory. Figure 140-150kpa is a good spot on a stock vehicle making 6-7lb of boost.

If one of those shows it's low, then either you still have a vacuum/boost leak, the BBV needs adjustment or the rotor coating is completely gone and causing a slight loss in boost pressure.