When I use the msfs propeller plane, the throttle often jumps around when taking off, and often when the throttle is full, it suddenly automatically backs up and the plane crashes. How to solve it?

User Support Hub Hardware & Peripherals
5

Have you seen this thread?

If you have assisted takeoff, the throttle drops and a bug has been filed.

See if that helps and then you may want to add a comment to the bug report.