mexicansoljah81
Member
- :
- '13 Mazdaspeed3
Check your grounds and check the connections on your Alternator. I checked one of my grounds, the one that connects on the passenger mount, and it was not connected possibly from the previous owner. I tracked it down and re-connected it yesterday and it made a difference actually, samll but it made a difference. I will for sure be doing a complete reground kit on my car to include a an additional power wire from the alternator to the battery. Basically almost the "Big Three" without replacing my Alternator with a HO Alternator as I already have a new better battery. HO Alternator is my last resort, been having power issues with dimming lights as well.
A code P0421 may mean that one or more of the following has happened:
- The catalytic converter is no longer functioning properly
- An oxygen sensor is not reading (functioning) properly
- A sparkplug is fouled up
So yes the Non-Fouler not being on would cause that. Glad you installed it and it went away and fixed your issues.
Non-fouler worked for me after adding the OBX headers.