Mat,
You will need the service password to reach the calibration function. You have a rectangular dash with a display on the left side and a circle of buttons on the right. If you know the password, turn on the lift and press the center button twice, this gives you the screen to input the password. The one and three buttons allow you to navigate through options. The 2 and 4 buttons get you into those options. From the factory the password is all 5's. Some dealerships will use the zipcode in your area. Once you get into the calibration screen, find throttle. Press the 4 button to enter and move the handle fully forward and hold for 3 seconds, do the same thing in reverse. Release to the neutral position then press the center button. Complete should show on the screen. If the throttle still has problems, suggest replacing the hall effect sensor. Good Luck.