C172 Throttle going to idle on its own

I use a mouse and keyboard. Seem to have started happening when I had to reinstall MSFS2020.
If I use my mouse or F3 to increase the throttle it will go to idle on its own. The strange part is if I have the parking break on it will stay at full. As soon as I take it off the throttle goes to idle on its own. Any ideas? I have done a search and cannot find any way to solve this issue.

John

Is it possible your assist settings got reset during the re-install? Or key bindings?