Logic Pro Midi Keyboard Randomly Stops

Question

Hi, I am fairly new to Logic Pro 9 and music composition software in general.  I have a Yamaha P85 keyboard that I am using with Logic.  I use an E-MU midi 2x2 to hook it up to my computer (imac 2011).  The keyboard has a midi in/out slots where I have a midi cable in the midi OUT slot.  It connects to my E-MU midi device in the midi IN slot.  A usb cable connects the midi device to my computer.  The keyboard is recognized in my computer MIDI settings and works in Logic Pro.  The problem is when im recording in logic or just playing, the keyboard will randomly stop for a few seconds (no sound when I hit keys) and nothing will be recorded during this period (if I'm recording).  After 1-5 seconds the keyboard will work again.  This happens randomly even when I'm not recording in Logic.  Another problem is sometimes, also randomly, a note will be held (sustained) when I'm not holding down the key.  Again, this happens in Logic whether I'm recording or not.  I have searched a lot online and read many forums, but I cannot find an answer.  Any help would be appreciated.  Thanks in advance.

Answer 1

So yes I am playing on the virtual instruments.  No separate audio device.  I have external speakers plugged into my computer so when I play my keyboard through Logic, sound comes out of my computer external speakers and not the keyboard speakers(I turn the keyboard volume off).  The problem I described happens for the various virtual instruments I have tried, strings, woodwinds, pianos etc.  In the Logic audio settings it says
Output Device:  Built in Output
Input Device:  Built in Microphone
I/O Buffer Size:  256 samples
When I say the keyboard stops, I mean no sound comes out of my computer speakers for a few seconds.  It is as if someone turns the keyboard off for a few seconds and then back on.  This happens in Logic when Im trying out different virtual instruments.  You are correct when saying it happens only when Logic is running whether I am recording MIDI or just playing and NOT recording.  I hope that makes sense.  It wouldn't be such a huge problem, but it happens so often it makes it hard to play or record something thats longer than 10 seconds.  Thanks for the help.