I have been dealing with engine light 420 for 6 months and cannot get it to go way.

I have had both Cat converters and sensors replaced (at Mieneke muffler and I think this is part of my problem). Have also recently replaced all coils and plugs, new KM air filter, deep cleaned the throttle body assembly and the light still comes on.
The dumb asses at Meinke are telling me it's not the cats that are causing the code again and want another $300 to do a deep diagnostic test to determine what the issue. Possibly timing chain or bad turbo.

Its a 2015 F150 Ecoboost Platinum with 152,500 miles. Its paid for and I really don't want to get rid of it.

Anyone had any similar issue??

 

did they put 49 state or cali emission cats on it? I have seen that cause issues before

 

To be honest I am not sure what the actual brand of Cat is. They are claiming it's a Ford product, but I do not believe them.

 

Do you have an exhaust leak at the head/manifold? This can suck in fresh air causing the sane code.


Highly unlikely.