I've just gotten the engine running after correcting a ground issue to the ECM. After running the car a day or so the 420 code poped up. I am a at home mechanic and was wondering what are the most common solutions by posters. After reading the story behind 420, one issue may be a air leak. I noticed earlier when I changed the air filter weeks ago, while the engine is ideling, every minute or so, I hear a large air sucking sound from the drivers side of the engine compartment. After a few seconds it stops, then 1-2 minutes it cycles again with no noticable engine variation. I don't know if this may be related to normal engine operation or not. In addition, I plan to pull and clean the o2 sensors, after inspecting the wiring, No work has been none down there, but who knows. I don't know if they got sooted up when I was working on the ground issue, there was a lot of crankling going on. None of the other possible fault listings seem applicable. The last resort will be my friendly expensive mechanic shop. My diagnostic code reader hasen't cleared the code possibly cause the conditions still exist. Thanks in advance.

 

more then likely new converters

 

The engine is running fine, no lack or acceleration or power. During the"cranking" problems the fuel and ignitions systems were dropprd out bu the ASD relay, posibility of soot was probably an error.
At this pointif I change both o2 sensors it would be cheaper than the shop. With the current heat wave here in New Orleans, I may take the week end off, but I expect to see if any voltage and resistance readings on the sensors indicate a problem.