Re: What's wrong with my pedal?
Do you still have warranty?
One of my first thoughts was to get back to your dealer and have it checked there.
If this is a used pedal and you really love it - what about selling it on and getting another one (used)?
You say you've tightened the spring. Springs do wear out (but that would usually be a gradual process) - try some fresh/different springs, might help.