random malfunctioning pump

[Jonathan Bond]

I've got a cannondale floor pump. Not the best, obviously, but it's somewhat decent.

Anyway, it's been doing a very strange thing for a while now, finally remembered to ask about it.
The gauge reads only while the handle is pushed (and held) all the way down, most of the time.
Sometimes it reads with the handle up, but usually the number will decline on the next few strokes,
and then not read anymore.

Any idea what might be going on? I'm somewhat worried about the accuracy of it too, could explain
why I got a pinch flat/dented rim yesterday too (besides a botched bunnyhop onto some nasty sharp
rocks and neglecting to check pressure by the "squeeze test").

Thanks!

Jon Bond