Originally Posted by
skycyclepilot
Considering the time and gas, it's worth looking into myself - besides, I'll learn something. The LBS provides excellent service, and would look into it while I waited, and would let me take a test ride. I just want to make sure it isn't something simple before I go to the time, expense, and trouble of making that drive. I'd hate to get there and it take them about two minutes to fix something I could have easily done myself.
Well so far you've tried a bunch of stuff and have failed so it appears you've reached your limit of know-how, so quit resisting. The lbs will allow you to watch what they do (Rather than living vicariously through a bunch of phantom responders who are shooting in the dark). You need to learn when to give up.
There's lots to check on a bike like yours, including a bent derailleur hanger, clogged cable stops (Carbon fiber blocking stuff), housing kinks, bad endcaps, etc. Let the pros do their job and learn something first hand.