tracing - strange case

Hi colleagues,
I ran into some strange issue, i have a scenario, on my app, which is performing bad-takes a lot of time.
- when i tried to pull a trace on this session performing the scenario, everything
is working well.
- when i take the trace off, then the performance is bad again.
i'm using 10046 level 12 to trace it.

any ideas?
thanks in advance
:confused:

My guess : the classic bind peeking case, see the last article from Thomas Kyte in Oracle magazine, it is explicited there...

Regards,

Chiappa