I also had trouble with my 8900, skipping stitches and tearing thred, had it to the dealer 3 times, and was told it is the needle. Meanwhile I have learned about timing, and I start to believe it is the needle. I was ready to write to janome, but than my machine purred like a kitten, and still does, going over valleys and hills. Everything is fine now, I hope you will get it going .when it works it is a fine machine