I don't have skipped stitches when the machine is straight stitching. The poor FMQ from the 201 could be due to me or just the way the thread comes out of the bobbin/race. I believe it is Wiki that shows a beautiful example of how the two different races, vertical vs. horizontal, work.
When the "Timing" is out, then you have skipped stitches or no stitches picked up. I don't.
I could have taken that last screw out for the race, but it was in there too tight. I didn't want to strip the groove in nut, someone before me already made a bit of a mess with that groove.
I checked the timing on that machine while cleaning it yesterday. Thanks to the manual on the Wefixit yahoo group site I was able to make sure what I was doing was correct. All is good! Cathy had already given me a quick lesson on checking timing on machines with shuttles. I applied that information on timing that she explained to me, readings from Wiki on how a stitch is made, and the manual information for my machine.
IF I happen to get skipped stitches, I always start with checking to see if I have the needle in correctly. Easy for me to forget which direction the needle goes since I have so many machines that are all so different.
I always try to take pictures of removing parts so that I have an order to removal, to see what it looked like before and after, and for future reference. Thank God I didn't have to do to much of that yesterday since Rain's blog has all the needed photos for this simple job.
While the "how to do the timing" on a Singer 319w is still fresh in your mind, you could do a tutorial to share with others here on the QB. Do you have a blog? IF so, you could post it there too. I followed Rain's excellent tutorial on his blog on the Singer 201. And the heads up on how to use the little silver Singer screwdriver while removing and installing the hook made life easier- no frustrations or bad works.