This site is being deprecated.
Please see the official X‑Plane Support page for help.
Not sure if this is the issue or not but don't forget that the saitek throttle quadrents have a detent switch on each lever (particularly useful for reversers on turbine engines) it's possible that those switches automatically assigned themselves to something. That aside, take a look in the axis asignment section of x-plane (joystick settings) and see if the little blue bar that indicates the current position if the lever behaves as it should when you mive the lever up and down (throttle up and down that is) if when you get down to zero% on the lever if it jumps to full then you will have to call saitek and try to get a replacement out of them.
This site is no longer being actively maintained.