Can a P0193 code (fuel rail pressure sensor circuit, high pressure) cause a knocking in the engine? The light came on and then the engine started knocking but only when the engine is fully warmed up. It is confussing the out of me. It doesn't seem as if there is lacking power but the RPM's is fluctuating between 400 and 800. feels as if it wants to die when I come to a stop. And everything sounds and operates fine when the engine is cold.