First off Debbie, sorry to hear your having problems , Can you remind me what kind of machine you have? and I need to know what kind of thread are you using? I have a lot of trouble with 40 wt. thread on my Janome ,it just doesn't like it . I can also recommend to use some poly thread ,it work very well when quilting and Leah Day recommends it for all her quilting. The thicker the Thread the bigger needle you need to use and make sure your needles are sharp not the ball ping kind that will make a big difference in your quilting. Its hard to tell but ask your quilt shop for sharp needles for quilting. Sounds like you have done all the proper settings, I just have a strong feeling its your thread and needles.
EAT!! SLEEP !! QUILT!!
My machine is a Janome Horizon 7700 and I'm using Isacord thread. I don't know how old it is because I bought it on Ebay. I had tried other threads on my machine and Isacord is what it liked best. I was starting to wonder if was the thread itself because I had another spool that did fine, until it didn't. Other spools I've had no problems with. I'm using the same thread in the bobbin to match the fabric. I won't swear by it but I'm pretty sure it's happening when I travel right to left and maybe as I'm going up (trying to relive all the frogging I did to remember ). As I said before, the needle was new, the machine was clean and the test piece worked like a charm! I wasn' t going very fast at all simply because I couldn't. The thread was snagging at the needle and the only time it stopped short was when the bobbin was real low and ran back on itself.
I really appreciate everyone's input!
Southwest of San Antonio