I've had this problem with my GN but I've been to busy with school to work on it. When I roll onto the gas I can pull 15-17 psi but when I punch it down it hits 15-17 psi then drops straight to 11psi and holds there. And at idle the bl is at 150 but if I touch the gas at all it goes to bl 127. The IAC is 24, TPS .44. I don't know what the problem and if you need to know more info I'll post it.