(^ Acura 2.5 LS, engine quits when driving?

My 96 Acura 2.5 LS, when driving along at highway speed will start to buck, the tach & speedometer go to 0, even though i'm still doing 50. Then when I pull over the enging may still be running or have died. Somtimes it will start back up, others it will just click like a bad battery. Tested it with a bat load tester, ok, also cleaned the battery terminals. Maybe a bad ground to the engine somewhere? if so where?