As cheap as the repair parts are, I would not have taken the shifter apart just to look at it without installing g-springs at the minimum. The problem really does sound like a broken g-spring retainer, from descriptions that others have posted. I never broke one in 15 years of using Campy.

If all else fails, try 2010 Centaur ultrashift levers. They are a lot more comfortable.

Certain spacers can be installed in the wrong sequence - more likely with loose cog cassettes. Still possible with Record or Chorus, but the spacer between the two pairs of cogs being wrong should really be noticeable.

See pages 25-29 of this PDF.

http://www.campagnolo.com/repository...s08_B_1007.pdf

I assume that the RD hanger alignment has been checked? If not, do that.

Some people find the RD shift cable tension to be mysterious. Always work your way up to the minimum tension that will make good shifts to larger cogs. Over tensioning could result in overshifting, but it should also make for poor shifts to smaller cogs.

The cable routing is tough to get wrong - the cable goes on the side of the bolt closest to the wheel. Routing the cable on the wrong side would make a huge change is the actuation ratio.