Thanks for the detailed response Andy, and everyone else for oil/clean the chain suggestions. I will try everything. Just wanted to make sure it wasn't obviously a worn cog.

Measuring the chain seems to say the chain isn't stretched. So if I clean and oil it up nicely with either chainL or wd40, and it still skips, would that be a pretty good indication it was the cog? Or at least that would be the next thing to replace before a new chain?

thanks again fellas