justins90

Before you even read this, please, no posts telling me to "take the truck back".

Long story short - I bought it (2013 Ecoboost F-150 XLT S-Crew, with 104k miles), catalytic converter light came on a few hours later. He told me they had changed the plugs. I researched and found these trucks get a lot of condensation in the intercooler. Found that plugs are supposed to be gapped to at least .030.
That said, I assumed the plugs had been put in without being gapped down, which let the condensation + boost blow the spark out, resulting in a heavy charge of fuel being unburned and passing through the catalyst, making the o2 sensor believe it was "low efficiency" or "P0420".

I was wrong about the plugs. They are gapped correctly, and covered with carbon as shown in the picture. Will a bad catalytic converter cause new plugs to be so carbon covered so soon?

Any information is greatly appreciated so I know how to proceed. And again, please no posts telling me to "take the truck back". Thank you for any assistance.

Feathermerchant

I am no expert but do all the plugs look like that? If only one, then you may have a bad injector. Extra fuel in the exhaust can kill a cat.

justins90

I just pulled another, and it is the same. Both of these were closest to you looking from the front of the truck back towards the rear. I pulled one on each side. The pictures above was two pictures of one plug. Here is the second.

oldguy1946

You are taking the dealer's word that the plugs were changed which is fine if that is what you want to do but based on their condition in the photo they were not changed by the dealer and could have been in there for 100,000 miles for all you know for sure. The bad plugs could have contributed to the cat cel. Install the new plugs and then check them again after putting on some miles and see if they look the same.

justins90

I can pretty much tell from the anti-seize on the plugs that they are new. I wish they weren't or I wish they were gapped wrong... not the case.

Bravo3eco

The reason they are carboned is that you have some serious misfire going on. Misfire from condensate. Weep hole in yet? The new plugs were misfired on and fouled. That raw fuel is dumped in the cats and o2 sensors. These will be bad based on the looks of these plugs. This particular truck is turning into a can of worms. It was definitely someones problem child.

justins90

It didnt have the weep hole, I did drill the 1/16 hope and some fluid came out as soon as I drilled.

Also just found that the air filter was not only disgusting, but a K&N one (oiled) and quite oily. Just replaced it with a non-oiled fram one for now. I probably should clean the maf sensor. It may not be reading right either due to the oil from the K&N

Feathermerchant

Do you have one MAF or two?

05 super

The Eco's dont have any..They have MAP sensors.
1 by the airbox..1 by the throttle body..and 1 on top of the manifold..The throttle body and especially the manifold ones get the dirtiest.

justins90

I intend to clean all 3 of them then. Any special procedure for cleaning them?