Code P0420...

[Shakey]

I know that this has something to do with the catalyst. However, I have all the symtoms of a bad coil pack. Could this code be pointing/symtomatic to/of a bad coil pack?

 

[SHOZ123]

Possible causes:

Use of leaded fuel.
Oil contamination.
Cylinder misfiring.
Damaged HO2S.
Damaged ECT sensor.
Downstream HO2S wires improperly connected.
Fuel pressure too high.
Damaged exhaust system pipe.
Damaged exhaust manifold.
Damaged muffler/tailpipe assembly.
Damaged catalytic converter.

 

[SHOWHAT9]

DTC'S

Also see if this helps