I can hit the preset scan, search OR volume and sometimes the F90 will just keep going scanning thru the stations or increasing volume as though I was still holding the button down. Any fix in sight?

Check your antenna wire, and make sure it is securely installed

Same thing happend to me one time, after I put the entire dash back togeher. I didn't think of testing the most basic functions. I got the DVD video to work while in motion with the bypass. I was so happy about this I forgot to connect the antenna input, I realized it two days later when I wanted to listen to a cubs game, quite annoying.

i know exactly what you are talking about. Its your touch screen. Basically the radio thinks you are holding down your finger on the screen even when you arent (I confirmed this happening on the windows CE Desktop too). All i can tell you is what i did, the 3.0 firmware helps, recalibrate your screen, and also try cleaning your screen with some Windex (don't spray the screen directly, spray the windows on the cloth and then clean the screen). Basically the touch screen behaved ALOT better after that, but it still happens sometimes. Good luck!