Sorry to bump an old thread but Im having a similar problem on a bike thats been sitting for a while. It will shift but its really hard to shift. The shifter I have is a Shimano sl-rs40. I've been attempting to teach myself bicycle maintenance so I want to say taking it to a shop is not an option.
When Rev.Chuck says "slide the housing" what are you referring to? The rear derailer and shifter work fine no hard twisting etc its just the front. I read in Zinn to adjust the limit screws but have gotten nowhere. Any help greatly appreiciated.