Have you purchased or replaced your bobbins recently??? I recently purchased on line, bobbins for my Husqvarna Rose, bobbins at a BIG BARGAIN price!! What a joke... they warp when used and my machine does all kinds of crazy stuff... It took me for what seemed like forever to figure this out... just a suggestion.... ;)

I had a similar problem a few months ago when quilting a throw for MIL. After doing all the standard things: rethread, change needles, clean bobbin area, etc. over and over, I finally discovered a nick in the Aurifil thread spool! It was catching the thread, stretching it out and finally breaking. I switched spools (I happened to have another) and HAD THE SAME PROBLEM! Since both were Aurifil, I am now leery about using this brand even though I know it's well-thought of and others swear by it.

I've had problems with skipped stitches when FMQing on my Bernina 750 when I've used a spray baste product. I think I must spray too heavily and get thick spots. It seems my "Sammy" doesn't like me to spray baste. Probably thinks it's beneath him!

I am also having problems with my big machine. Finally gave up and took the bobbin case to the sewing machine man. He doesn't think there is anything wrong with the bobbin case, but rather a spring is gone from somewhere in the machine. So, am taking it in for him to check, clean, ect, ect.
It is53 yrs. old and this is the first time I have had problems with it. I still sews like a dream and wouldn't part with it. Is a Japanese Singer and has sewn millions of miles!! The Featherweight is fine for now; suppose it will have a problem when I get this one back!!!(Take turns.)
Mariah

Check to make sure needle is in correctly.

If you are using cheap (low quality) or very old thread, that may be contributing to your issues.

You have gotten good advice. Hope it helps you.

This reply is coming late,but...have you tried flossing your machine? Dental floss, threaded onto machine just like threading from a spool. Don't go through the needle. Gently pull floss through for a yard or so. Many times this will help.

Glad to hear your problem is fixed!! What did it turn out to be?