I did not use my bike for quite a while, but remember the last time I used it it was working perfectly. This could not be the adjustments on the derailleur. I then checked the cable tension, it looked fine. So I disconnected the cable and tried the shifter and noticed it did not go all the way up with the cable disconnected! That is where the problem was! I unscrewed the cap of the shifter and cleaned the old grease with brake cleaner. I then sprayed new lubricant and put the cap back in place. I reattached the cable and the derailleur worked just fine. It seems to me that these shifters are very sensitive to bad grease! I suggest you try this before you play with the adjustments as this might save you a lot of time!