The B1378 Code comes for the error of the engine and the problem seems on the body. The problem of B1378 Code can be solved easily and you do not need to change any part of the engine for solving the problem. A failing oil pump can be a reason what is called oil starvation, which is nearly always lethal to any engine. Above cam engines are particularly at risk, since the cam and valve train are beyond from the pump than they are in pushrod engines. Oil should be of a good viscosity, what means it requirements to be light sufficient to move rapidly.