You could use the Session Frontend → Profiler to capture a session and then step through and see what is going on with the network client or server. This should help point you in the right direction to fixing / finding the problem.
It is what my team has been using to find out how many packets are being sent. What functions are doing what, ect. Great debugging tool for things like this.
It basicly allow you to record a snapshot of time and then step through the stats and see what is going on.