OK, I'll get in there tomorrow and look for stuff gunking up the works. This bike has shifted fine for years. Last week I was riding it and it started shifting sloppy and then would not shift out of the big rings. I got it home and immediately saw that the metal of the barrel adjuster was ripped apart so I assumed that was the problem. I had to swap out cables too and I installed a new adjuster and cable. Same symptoms: the bike shifts around the small cogs OK but get her into the big ones and there she stays! The cable is slack all the way up the down-tube yet the derailure stays all the way left. When the cable is disconnected the derailure swings all the way back to the right. Humm.......