DTC 5-4-4 Misfire More Than 1 Cylinder, TWC Damage

5-4-4 MISFIRE MORE THAN 1 CYLINDER. THREE-WAY CONVERTER DAMAGE

Preconditions for DTC
^ If the ECM registers 6 - 50% misfiring, depending on engine speed and load, during 200 engine revolutions (500 ignition sequences), the control module checks if this misfiring comes from one specific cylinder or from different cylinders.
^ If only one cylinder exceeds the limits, then one of DTCs 4-5-1, 4-5-2, 4-5-3, 4-5-4 or 4-5-5 and 5-4-3 is set, followed by DTC 5-4-5, then one of DTCs 5-5-1, 5-5-2, 5-5-3, 5-5-4 or 5-5-5 depending on the relevant cylinder.
^ If several cylinders exceed the limit, then DTC 5-4-5 and 5-4-4 are set, as well as a DTC for the relevant cylinder.

Substitute value
^ Fuel trim shut off.

Fault sources:
^ Defective spark plugs, ignition cables, distributor cap/rotor, ignition coil or flywheel/tooth wheel.
^ Faulty spark plug.
^ Blocked/leaking injector.
^ Uneven compression.
^ Leakage between cooling system and cylinder.
^ Moisture, flashover in ignition system's high-tension section.
^ Intermittent break, intermittent short circuiting to ground, intermittent short circuiting to voltage supply, contact resistance or loose connection in ignition system's low-tension section, in injector circuit or fuel pump circuit.
^ Too much engine oil.
^ Air leakage.
^ Fuel pressure and residual pressure.

Fault sources not included in the fault tracing process, but which may still set a DTC:
^ Fuel stoppage.
^ Insufficient fuel level, resulting in fuel starvation.
^ Water in the spark plug recesses.
^ Incorrect fuel or dirty fuel.
^ Repeated cold starts whereby the engine is never given sufficient time to reach normal operating temperature between each start.
^ Puncture in a front tire.

Fault symptoms
^ Engine does not start, or is difficult to start.
^ Engine runs unevenly at idling speed, or jerks severely while driving.
^ Poorer performance.
^ Higher emissions.