If you think about, a quick tempo means they will look to get rid of the ball as quickly as possible, if there is not a good long direct pass it will end up short.
When short and slow I guess they still have problems picking people out, so, who are you playing as? Perhaps your players aren't good mentally so aren't creative for example, or they lack compusure and so on. Also, look at how much CF you are giving your players with each situation
So you've gotta decide which style suits your players and stick with that. If this does not help there is plenty of useful info on passing, etc in the tactics bible.
Why is it 
Linear Mode
