steko

Actually it really was the issue. Maybe it's because i am using the Xsaitek plugin and not the plugin provided by saitek itself. So if i put the switch to "close" position the shaking immediately stops. The switches in the cockpit however are not moved by that action, so it was kind of tricky to determine the cause.
 
But the more elegant way for people experiencing trouble with that kind of stuff is to put a "xsaitekpanels.ini" the aircraft folder and edit it.
Look for the line that says "Cowl Flaps enable = 1" and change it to "Cowl Flaps enable = 0". Also you should use that for the magneto switch because it'll prevent you from engine start.
 
 
So thanks for the help.
Problem solved