My computer has been intermittant for a while. Its a wired, sigma BC1606L. I've tweaked the sensor and magnet. The wheels are true and the gap is as close as you can get without touching (1-2mm at most). I've noticed over the past few weeks that it seems to work fine when temps get over 100 degrees (evening) and it doesn't work at all below 100 (morning). Below 100, the time displays, sometimes it will register 0 MPH, but thats about it.

I'll probably replace it, but WTF?