I've had it for four years and no one can seem to adjust this thing. When I'm in the big ring and the smallest cog, the outer plate rubs. It is not because it is at its limit because if I pull the cable, the derailleur moves away from the chain. When I'm in the middle ring and I try to use the largest 2 or 3 cogs, the FD will auto-shift to the smallest ring. Shifting from the middle ring to the big ring is hit or miss.
It sounds like the cable is too loose. When I get it back from the shop after they adjust it, it will shift great for about five miles and then it reverts to the same old problems. Is it possible for the problem to be related to the in-line barrel adjuster? When it starts to screw up, I can fix it a little bit by playing with the barrel adjuster. I know that you shouldn't have to do that one it is adjusted. It just seems like the cable stretches really fast. Should I try replacing the barrel adjuster or maybe take out the inline and replace it with the regular kind?