code 1315 on my toyota tacoma 2001 2.7

Question

Can you tell me why my engine just quit running and after I pulled over it started right back up untill I tried to get back on the freeway then it did the same thing over and over again I had the engine checked and the code 1315 came up which means #4 coil bad" the ? is why did the whole motor quit??? shouldnt it just miss on that cyl ?