totally not familiar with your LA machine, but I find lots of support for my Gammill on the Gammill FB page, you might check to see if there is one for the Juki. I'm assuming it has a stitch regulator on it, on my LA, the tech told me that if the needle leaves a hole but the thread doesn't stay in, then it's the tension or the hopping foot height or timing off, etc. If there is not hole, just a big space, then it's to do with the stitch regulator. Hope you get it figured out soon, can be so frustrating!