Thanks for this, Jim. Already reset to defaults, before re-install. Using the default 737, start a flight, the engines are running at 58%. F1 will slow this done to 20%, then they'll spool up to 58%. Opposite happens with the F4 key. Even with the Saitek unit dis-connected. This is common to all default aircraft. I have not installed any add-ons.
Cheers, Dave.