DuraAce shift lever hangs up when shifting down to small chain ring
Hi all, this is my first post and I'm hoping someone else has encountered this problem and can help me out. My road bike is equipped with DuraAce 9-speed. The problem, which I've been having for quite a while, is that the left STI shifter (brake handle) hangs up and doesn't want to slide sideways to allow a shift up to the big ring. Never a problem shifting down to the small, only up. To make the up-shift I always have to "play" around with it, which you can imagine gets pretty frustrating when you need the shift. The other oddity is that once I've freed it up, it shifts both down and up without a problem for a short time. But after I ride on the small ring for a while it's again hung up when I try to shift up.
Has anybody had this problem or have one of you expert mechanics run into this before? I could be wrong but the problem appears to be with the shift lever or maybe the cables, not the front derailleur, which seems to be fine when I loosen the cables and move it by hand. Please tell me I don't need to chunk out $400+ for a new set of STI shifters. Thanks for any help you can give me!