Front derailer sticks
 

My Campy FD (about 8 years old) a couple times on each ride gets stuck on the large sprocket. Pushing on the thumb button to shift down to the small wheel feels like it just won't budge. I've found that to be able to downshift I first have to give the upshift lever an extra little shove, after which the downshift button works and lets me shift down. I changed the cable and housing with Campy parts, but this is still happening. I've also put some oil on the FD pivot points. Suggestions please?

I assume the shifters are "Ergos" from your description. There are a couple of springs and ratchets in them that eventually wear out or break and have to be replaced. Fortunately, Campy brifters can be overhauled and repaired.

If you have an LBS that is familiar with Campy components they can rebuild them for you or you can get the parts and tackle it yourself. It's not quite rocket science but it is a bit tricky. Branford Bike (http://www.branfordbike.com/) sells the repair parts and has a repair booklet for or will do the work for you. It isn't cheap but it's less than replacement.