For some time I have a P0420 left bank (with the VSC and TRAC lights on) and not been able to identify an issue. Occasionally when on the freeway the lights would clear but come back with a cold start. Now the check engine etc lights have gone for good but the OBD meter still shows the P0420 code.
So far the warnings have not come back and the code has not cleared after a few days driving.
I have two questions:
The shop put in new plugs before this started so might a bad plug job be likely?
Is it a good idea to replace the O2 sensors anyway after 225,000 miles even when static data looks good and cat has a 70F temp increase? I have had associated increase in fuel consumption.
Regards,
So far the warnings have not come back and the code has not cleared after a few days driving.
I have two questions:
The shop put in new plugs before this started so might a bad plug job be likely?
Is it a good idea to replace the O2 sensors anyway after 225,000 miles even when static data looks good and cat has a 70F temp increase? I have had associated increase in fuel consumption.
Regards,