Hi Pevries
I'm not from Laminar Research, just a fellow simmer in the UK, but when you say "even if I don't use a joystick", did you mean that the joystick wasn't plugged into your PC or that you were using a yolk/throttle combo and the throttle still goes to full?
Also, do you mean that the throttle setting whilst flying in X-Plane goes to full even though the physical throttle is at idle?
Lastly, can I assume that you have fully calibrated your joystick etc. within X-Plane?
Regards