Went for a ride after work. At first I was having the same issue; I could get it into the big ring if I was in lower gears but not in higher gears. I pulled on the cable directly trying to shift it, figuring if I could it was a cable tension issue and if I couldn't it was a limiting screw issue. I wasn't able to shift it this way, leading me to believe I'd have to adjust the upper limiting screw after I got home. But after riding only a short while longer, I tried using the shifter and it worked...and worked fine on the rest of the ride. Although the ride was extremely flat and I could have easily made it in about 3 gears, I worked both the RD and FD through all the gears and both seem to be working perfectly fine right now (knock on wood.) I guess it just worked itself out...or maybe the derailleur Gods were feeling benevolent today? Oh well...there were a lot of good tips in the thread which I'm sure will come in handy because I adjust my derailleur often (it's that "perfect being the enemy of good enough" thingy...)

After posting this now I wonder if maybe the FD is sticky? Would it hurt to squirt some grease on it, or maybe WD40?