I have Red shifters from ca. 2009 on my bike. Both derailleurs are new - the rear is a wifli model and the FD is that new yaw contraption. I recabled the rear when I replaced the rear derailleur in March and installed an 11-32 cassette. Everything has worked as expected since then until Saturday. The cable routing is internal (2012 Specialized Roubaix SL3 frame) and I did the california cross inside the downtube. I've had the frame since about March of 2013 and it's been configured this way the entire time with no difference in shifting performance from my previous externally cabled, non-crossed frame.
I was participating in a century and after lunch, I noticed that my rear shifter was really stiff when shifting to a larger cog. Shifting the other direction seemed normal. It seemed to get a little better later in the day and I had high hopes it worked itself out (hah!) but Monday's ride featured stiff shifting again. To quantify what it feels like, it's like I've reached the end of the cable travel and I'm over shifting, but that's not the case. I have not paid enough attention to notice if it's worse at one end of the cog or the other. It was an immediate issue though, not gradual, which leads me to think that something happened. Before lunch, fine. After lunch, what the heck. Very noticeable difference.
While I was digging around, I found a recall for SRAM Red wifli rear derailleurs and mine is affected by the recall. It doesn't appear to be contributing to my current issues and the rear derailleur moves freely by hand, so I don't think that's my problem.
So... later this morning I'm going to put the bike on the stand and check it out. After doing some digging around on the internet, it sounds like the two most likely possibilities are that there's something interfering with cable travel, possibly where the cable exits the frame and goes under the bottom bracket. Another possibility is that the shifter itself is dirty or gummed up - I've seen stories about people cleaning the ratchet mechanism without disassembling the shifter, and that seems to help.
Any tips on what else to check? If I can't figure it out I guess I'll have to find a local shop that represents SRAM and see what they say but I'd rather ensure it's unfixable by me before handing over my only completely assembled, functioning bike.