Hi guys I have problem with my 02 wrx.
After moods on my rex witch are coob stage 2 map turbo back exhaust, I noticed boost waiving when full open throttle. Turbo is pumping to 18 Psi peak and coming back to 12 Psi and again to 16-17 Psi. I canít get full power and is little bit annoying. I checked turbo vacuum lines no problems waste gauge is moving and solenoid is connected correctly no cell. I noticed little bit oil in intercooler. I need to put around 1 quart refill between 3000-mile oil change, any ideas.