DTC P0300, DTC P0301, DTC P0302, DTC P0303 Or DTC P0304: Description

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor (POS) signal to vary, ECM can detect a misfire. The misfire detection logic consists of the following two conditions.

1. One Trip Detection Logic (3-Way Catalyst Damage)
   
   On the first trip that a misfire condition occurs that can damage the 3-way catalyst due to overheating, the MIL will blink. When a misfire condition occurs, the ECM monitors the CKP sensor signal every 200 engine revolutions for a change. When the misfire condition decreases to a level that will not damage the catalyst, the MIL will turn off. If another misfire condition occurs that can damage the catalyst on a second trip, the MIL will blink. When the misfire condition decreases to a level that will not damage the catalyst, the MIL will remain on. If another misfire condition occurs that can damage the catalyst, the MIL will begin to blink again.
2. Two Trip Detection Logic (Exhaust Quality Deterioration)
   
   For misfire conditions that will not cause damage to the catalyst (but will affect vehicle emissions), the MIL will only light when the misfire is detected on a second trip. During this condition, the ECM monitors the CKP sensor signal every 1000 engine revolutions. A misfire malfunction can be detected on any one cylinder or on multiple cylinders.