Hey, I'm not 100% sure if this is the right spot to put this, if not...sorry.

Anyways, I'm trying my best to learn how to do basic maintenance on my bike so I don't have to rely on going to a shop on the weekends and forking over more money. My problem lies with the front derailleur. I needed to adjust the limits on them, got them where they needed to be, and thought everything was hunky-dory. After a little ride, my chain started rubbing when I was in my hardest gear.
When I shift to my big cog in front, and little in back, it rubs pretty bad. This is the only time the chain rubs (other than if I cross-chain). What happens is when I shift up, the derailleur goes all the way to where the limit screw lets it, then it slides to the left and rubs the chain.

My first thought was to mess with the tension of the wire: no dice.
Second thought was to let my limit screw out more so it could maybe move further, and when it slides it will go to where it needs to be. Again, did not work.

It seems like no matter what I set the high limit screw to, it only goes out so far, then will slide back. I'm really hoping to get it fixed tonight so I can ride tomorrow. If I gotta take it to the shop, I'll most likely miss my chance to ride. Any help is greatly appreciated.