Originally Posted by
TromboneAl
I think I solved it.
I removed the cable and found that the RD moves crisply when pushed with my hand.
I saturated the brifter with WD-40.
I went for a ride, and it was still happening. Then, while riding, I adjusted the tension with the adjuster on the downtube. I don't know if all bikes have this, but I can flick this little lever to one of about five different positions.
For the rest of the ride, every single shift worked perfectly.
So, my conclusion was that I hadn't adjusted things properly, and the RD wasn't lined up just right, so it was somewhat between cogs.
Hey! Great you found your problem! One thng that I do that saves a lot of time is to move the rd/fd using just the cable independent of your shifters! Just grab the cable where you can and move the rd/fd in and out just by pulling on the cables. It eliminates guessing that it is your shifters(easier to "work on") rather than that complicated rd/fd! Adjust your rd/fd then work on your shifters! Have fun!