The turbo light just warns of high boost pressure. I think mine is broken, I've never seen it turn on, even though my wastegate line is off and I sometimes hit the overboost switch.

Do you see any exhaust smoke when you are running at full throttle and 9.5 psi? If you had a boost leak that only shows up at 9.5 psi, then you would start to run rich after that, and you should be able to see black exhaust.

Please be careful running around like that, we don't want you to get carbon monoxide poisoning!

So, what RPM do you hit 9.5 psi at? After you hit 9.5, the car continues to accelerate with the 9.5 psi?

If you aren't running rich, then it sounds like a "weak wastegate" or something like that. I don't know too much about wastegates, though, sorry!

Greg