When you pull the shift lever down, does the front derailleur move towards, or away from the frame? If it moves towards the frame, it could be that you pulled a teeny bit too much slack out of the cable. That said, I doubt this is the cause, since the only front derailleurs I know of that operated this way are a few models of older Sun Tours. More likely, you need to adjust the high setting of the front derailleur by loosening it a bit. Try 1/2 turn increments, and test until you have it right.