4P0420service engine soon is blinking

Question

nissan maxima 2004P0420service engine soon is blinking when I accelerate and the car is shaking when is idle or when I just turn on

Answer 1

The P0420 code is set if the Catalytic Converter is not working properly, but that shouldn't cause the engine to run rough. 

You could start by changin the spark plugs, you may also have a faulty ignition coil.