computer problem
 

Have a Bontrager Trip 100. Everything works, but speed and distance is erratic. Speed bounces all over the place. One moment it says 12 and then it will jump to 22 or 16. The distance does not update consistently. Any thoughts?

If its wireless, it could be getting interference, do you have a headlight on when this is happening?
It could also be that the gap between the magnet and the sensor is not close enough.