Hi Folks, I have been loving my rad power wagon for the last year and a half and recently passed 2500 miles. Only recently has it began to surge when I pedal (in any PAS level). On the screen, the watts delivered in number form reflect what I am feeling. 50 watts jumps to 300, drops to 150 then up to 500 etc.  when I first noticed it, the twist throttle would not respond at all. Like all things, diagnosing is tricky in that it is inconsistent .  Now the throttle works fine.

I noticed that the Rad folks have tutorials on replacing the controller, but no mention (that I can find) on why one would need to replace that item. Any thoughts/advise would be appreciated. Thanks.