(I'm assuming this is still cable controlled in '06). Check the cable between the servo and the throttle. Mine was a little rusted and sticky this year and made the perfect pass work exactly like that. I just removed it, cleaned and lubricated and it's fine now. If you google PP troubleshooting they walk you through a test for this but basically you turn the engine off, give it half throttle, and turn the servo knob both directions. The throttle must move IN BOTH DIRECTIONS to correspond with you twisting the servo knob. If it's corroded and sticky it will only move in one direction.