Ok i'm not new to the 4g63, but i am kinda lost right now. Looking around i read that the evo when it's stock runs about 19psi and tapers to 17psi. I installed a Stewart Warner vac/boost gauge today, which is no big deal I have done numerous ones in the past. I run the car and in 4th and 5th gear, I hit 18psi but then it drops very fast to 15psi and then comes up and goes down. Does this sound normal? If not then any sugesstions? I have a extreme motorsports DIS filter kit and a Greddy type-s with the single spring mod. Could it be that the BOV is opening early because of the single spring? Please someone shed some light on this for me. Thanks in advance

Lewis