I have just bought my first wrx after trading in my legacy and noticed that the car seems to "pulse" when the throttle is wide open. Especially in 2nd and 3rd gear. It feels like the throttle is being lifted very lightly and very quickly on and off until about 5,000 rpm then smooths out. The tach doesn't show any unsmooth movement and I don't think thats its any type of ignition break up. Just wondering if anyone has any ideas what could be causing this.