X1 Producer Lurching on Playback/Record using MOTU 2408 for Audio and MOTIF XF8 Midi

I apologize in advance if this setup issue has been already answered.  If so please give me a link.
 
My problem here is that I want to have  a project with both Audio and Midi data in it.   I setup my Sonar to use my MOTU 2408/424 system as the clock master and clock is set to audio.  I record audio all day long and it seems fine although I note the time values during playback and record kind of lurching along in chunks.  I verified im using same 24bit/48000 settings in both MOTU PCI interface AND Sonar X1d.   When I try to record audio with audio metronome enabled the playback and metronome are also out of sync.
 
Then I try to record midi and the midi playback is awful.  Lurching and way out of sync.  I have also tried with and without the audio metronome to no avail.  I note that if I reset the clock to internal, record midi, go back and reset it again (Sonar always resets the clock to audio for some reason) it actually sounds ok.  I cant record audio with this clock setting tho.
 
I was thinking about buying X2 but really need to solve this issue before I do.  Can anyone give me some advice on what the heck may be going on here?  Is there some special stuff I need to do to use a 2408/434 with Sonar X1?
 
Im using a Win7 x64 machine, Sonar X1d (64bit), and 4 GB Ram, I7 box.
 
Thanks in advance,
Homey

Actually im not using any soft synths or plugins at all.  My midi data is coming from the MOTIF XF keyboard over their USB midi driver.  Im also going to try to update my MOTU drivers today to see if that helps.

If the now time is lurching try pressing the pause key on your computer keyboard.

Thanks for all the suggestions!  I think I narrowed it down to having two sound cards tho.  Even though my 2408 was timing master on both rec and playback my windows sound card was still in the Sonar list of devices it could use.  Once I unchecked that, everything seem to work fine.   I guess ill try to look for how to have both in Sonar at some point since I would prefer using my normal windows sound card as a playback monitor and keep all 8 I/O's of my 2408 free for the main record and playback system.  But giving up channels 1/2 on MOTU for playback at least solved this problem for now with the windows sound card out of the list.  

An interesting note with MOTU driver (latest).  When I tried the ASIO driver Sonar complained "you don't have a audio device" but launched anyways and it showed my 2408 ASIO audio (which actually worked).  I went back to WDM drivers for 2408 and Sonar didn't complain any more.

I did try upping my midi prepare buffers from default 250 to about 900 and it didn't make any difference.  I also verified my system wasn't running anything significant in the background.