My Juki is really sensitive to lint buildup. If I don't keep the bobbin area really clean it messes up the tension. Mine has fmq'ed on everything and the only real problem I had was when i was trying to quilt a heavy T shirt quilt with French Fuse interfacing behind the shirts. The only solution I found was to use a topstitching needle. They have a longer eye and so they don't skip sts like the regular needles were doing.

Try your fmq with your feed dogs UP, and less pressure on the pressure foot. That works really well on my Juki-- helps me to make more even sts.

Also your 'micro sts' sound like the the quilt got stuck in some spots-- maybe where it was thick from seam allowances? The feed dogs up will help keep moving the quilt along as you fmq.

So far I have only used my Juki 2010 for straight stitching. Want to learn free motion quilting but too many other projects in line first. I was watching a video this evening where Rob at Man Sewing is giving great, free lessons online. Tonight he mentioned just what you describe. He showed how it acts and he said often you will be using the free motion foot and forget to drop the presser foot and that's what happens. He said with the free motion foot it is very hard to tell if it is up or down, especially where the quilt is thick. He said it can cause you to go nuts trying to find the problem. He says to remember to always check that the presser foot is down. Said it has happened to him and he has been free motion quilting for years.

Just Jan - I have also forgotten to put the presser foot down on occasion. Usually catch that one pretty quick. It does indeed make a mess.Good luck with your FMQ when you get to it - normally it's fun, my favorite part of quilting. SewBiz Girl - thanks very much for the suggestions. I had not heard of a top stitching needle, but does sound like a very good idea....
It is so nice to be able to get suggestions from Board members. Thank you everyone!