This is really hard to explain so bare with me.

Normal boost is anywhere from 7-9psi on my car right now.
For some reason, when I floor it, boost will almost never rise above 6psi.
If I use about 40% throttle. It will stay at 8-9psi. If after this time I press the gas all the way down. It lowers itself down to 6-7psi and will stay there. Othe times it wont rise above 5-6psi.
This is very annoying, as you can FEEL the difference in power. Basicly if I floor my car it FEELS slower then if I only use 40% throttle. What could be causing this?