My 2003 Hollowpoint (LX front, XT rear) has recently begun ghost shifting badly on the trail. Mainly on middle chainring & between middle sprockets. I'm no mechanic but I've been adjusting derailleurs for years. On the stand the bike shifts PERFECTLY, and no probs on road either. I thought the shift cable may be binding, but when I disconnect it it slides freely. LBS tune-up did not help (they also verified that the shifting on the stand & in their parking lot is fine). I am guessing that the suspension movement slackens the cable. Would shortening the cable housing be something to try? Any other suggestions?