Boostfan

2011 Eco with 152K miles, engine light on again....30K miles ago the codes were cat/converters, misfiring cylinders, possible intercooler issue - running just about the same way this time so ASSume it is same issue....Last time replaced cats and plugs and ran fine. Thanks in advance for any help.

tomb1269

If you did not resolve the issue that clogged the cats in the 1st place (usually a slight rich condition in the motor due to a small intake or vaccum leak) and particularly if you installed after market cats, you most likely are looking at replacing them again. You could have lazy O2 sensors, you need some time on a scanner viewing the live data to see what is happening in the engine.

Aboostedf150

the first thing you should always do is clear the codes,as sometimes one code causes the other codes....a Hard code is what you need to worry about,after clear drive,and see which one comes back first,and figure out that issue first....You could of had water come in the intake,causing the miss fire on a cold rainy day,and then the cold water hits the catts causing a false code.. While that is just a example i have seen that many times over 20 plus yrs in a shop..

Ecob01

I would try changing the plugs first and clear the codes. the new plugs they put in the Ecoboosts seem to have a lot of problems. sometimes they don't throw codes at all but are the problem. My truck would act up only under hard exceleration or towing, warning light would come on engine would stumble but no error codes change the plugs and all fixed.