After months of wondering I found a "solution" to a problem with my throttle staying partly open and not going to maximum.
Some of you might find this very obvious but here goes:
If you set the sensitivity of control surfaces with the "simple button" all axis are set. This includes the throttle axis - which you could easily oversee as it is not directly in the window (you'll have to scroll down to see it - which I never did). So if you set all axis close to minimum, the throttle has a very limited range as well.
I think a lot of people having the problem with planes creeping forward despite the throttle being closed and/or lack of power on full throttle could solve it by looking at the sensitivity setting of their throttle.
It's often suggested you should change the value of the throttle axis in the FS2002.cfg file to 134 or something which is correct of course, because this is equivalent to setting the throttle sensitivity to maximum in the settings screen!! It will however jump back to 30 or something next time you adjust sensitivities using the "simple" button......
Bye for now
AJ