That darn thread can be the problem. Clean out the bobbin area, that's the first place I go because on the new machines, that's one of the few things you can maintenance.
I was getting skipped stitches and the last thing I did was change the thread and lo and behold! Perfect stitches. The thread was old. No problems since!
Also check your needle to be sure it isn't slightly bent. If you can't tell, just put a new one in anyway.