Cylinder #1. #2. #3. #4 Misfire

NAME OF CODE:
Cylinder #1. #2. #3. #4 Misfire

WHEN MONITORED:
With the engine running.

SET CONDITION:
Absence of spark, poor fueling, or poor compression.

THEORY OF OPERATION:
When a cylinder misfires, the fuel/air mixture in that cylinder is left intact. In the exhaust stroke, this mixture of raw fuel and oxygen is driven into the exhaust system. At the site of the catalytic converter, because of the high temperature of the component, this volatile mixture will combust and result in a rise of temperature of the catalyst. The increase in the catalyst's temperature is linear with the misfire rate. If misfires occur persistently, the catalyst temperature could go as high as 1400° C. The catalyst efficiency is at its maximum value when the temperature is between 400° C and 800° C. Any temperatures above this range will result in permanent damage to the catalyst.

POSSIBLE CAUSES:
- Ignition coil circuit
- Spark plug, wire, or connector
- Fuel pump or filter
- Mechanical engine problem
- EGR system