When error code read p1391 ckp or cmp sensor signal intermittent what do that mean?

Error code P1391 indicates an intermittent issue with the crankshaft position (CKP) or camshaft position (CMP) sensors. This means that the engine control module (ECM) is detecting irregular signals or fluctuations from these sensors, which are crucial for proper engine timing and operation. Such intermittent signals can lead to misfires, poor engine performance, or difficulty starting the vehicle. It's advisable to inspect the sensors, their wiring, and connections for faults or damage.