Stopping the outside run, hb screens

I have a stout run d if teams go up the middle, and my passing defense is fairly solid as well. However, a lot of the teams I've been playing against will just run to the outside with their speedy 92+ spd guys and for some reason it has proven difficult for me to cover. I have tried spreading my LBs and DL but it still doesn't seem to work. Also, I've been seeing a lot of these goal line formations with outside tosses, which are cheesy I think, but still I'd like to be able to stop them. What should I be audibling to in these situations, and its gotta be something that also guards for the screen, because these guys that continue to just go for the outside runs are also the same guys that throw like 10 screens a game.

I'm tired of losing games to guys that never throw a single pass beyond the line of scrimmage.

edit: I should add, I've been using the Cowboys 3-4 playbook on defense.

You have to mix up you D. I'm like that sometimes I wanna play it safe and try to stay with the same D. Ok now if you notice they are screening you to death play man coverage!!!! It is alot harder to screen on man coverage. The outside runs just put you de's in contain that will help with the outside runs. I use a different D play every down unless I know for a fact what they are doing they I man up.