What is a misfire? Is a misfire when the cylinder does not fire? Is it when the cylinder fires too soon or too late? The answer is “yes” to both questions. Some misfire complaints are a flashing check engine light, and a P0300 to P0312 diagnostic trouble code (DTC) indicates that one or more cylinders are misfiring. This is the easiest misfire to diagnose. But, what if there are no codes and a misfire is intermittent? This is where it gets complicated.
Andrew Markel tackles this tricky diagnosis in his article from our sister publication Underhood Service.