Looks like we are having to give up agility with one of our dogs for almost the same reason,hes 2 yrs old and when at agility hes so unpridictable,some times hes great,gets contacts does weaves etc then other times he gets so hyper he wont do a damm thing hes meant to do, he runs off barks at other dogs,its a hard desision to make as we feel he really needs agility to focus him,hes a lakeland x jr and despite lots of training in obdiance and having a behaviourist to help us in the past hes a law unto himself at times ,im sure if he could he would stick 2 fingers up at us at times (Please excuse spelling mistakes its late but my brain is going round and round thinking what to do with Rusty next)