Greetings everyone. New to the group. I'm looking for some assistance in troubleshooting. I have a 2012 XLT EL, 5.4 3V, with about 101k miles. It's been running like a top up until about a month ago. It started running rough and eventually began misfiring. I used to have a 2002 F150, so in my experience it was a bad ignition coil. I got the code read to find out which one and it returned 0430 steering me toward possibly O2 sensors or Cat.
As I was contemplating what to do I went and got the oil changed and had them read the code again. This time it returned additional codes of 0300 and 0307: Random misfire and #7. That helped me narrow it down (I thought) and would fix the 0430 code possibly too. Because of the mileage, I was just going to do all the plugs and ignition coils myself. I spoke with 5 different people/mechanics and they all gave me the horror story of 2 piece plugs and to not change them myself.
So I took it to the stealership and let them rake me over the coals to swap out all the plugs. Of course they always come back with more, but I wasn't prepared to sacrifice my first born for new ignition coils at this time so just paid for the plugs. They said Bank 2 cylinders were showing between 1-3% compression change.
I went to Autozone, got a whole set of Duralast coils and changed them in 20 minutes. The truck ran fine for about 2 miles and began missing again. "Son of a .....". So I got the codes read again. This time 0430, 0300, and 0306....#6....WTF? So I thought, maybe I got a defective coil in the set of 8. I went back to Autozone and used the warranty to swap it out. Ran "ok" on the way home. Next morning, missing again on the way to work. Ugh.... Soooo...I've had new plugs replaced by the stealership and all new ignition coils and still misfiring. I'm stumped. Could this possibly be an electrical issue with the wiring and signal??? Please help.
Thank you much.

 

We need to start someplace and it might as well be with the oil you are having put into the vehicle. If you do not know what type/grade oil it is supposed to have used in it check the recommendation in your owner's manual. Then check what kind of oil whoever is doing the oil changes is using and go from there. If the incorrect oil has been or is being used that might get into the picture. I believe you are going to need more than a code reader to determine the actual cause. Lets see what other suggestions are made and hopefully my suspicions are wrong.

 

 

The reason I inquired about the oil used was , problems developed with the variable valve timing system and performance suffered. From what info you provided it would seem that should not be the problem. There is a test procedure called "Freeze Frame" that capable scan tools can pull up and that should show the engine parameters at the time the codes were set. Those parameters are usually compared to known good parameters and anything out of the ordinary would be shown. A lot depends on the person examining those numbers and conditions.

 

Interesting.

I drove back and forth to work today and when I got home I checked the codes again. 0307 was added for cylinder #7. So it's not just contained to one cylinder...

 

We don't like to provide misleading info, but Fords for some reason will give a misfire code for one cyl while the troubled cyl is a different cyl. That is why you cannot always go by what a code reader shows. There must be something going on with bank 2 of the vehicle and a more detailed check is in order. Bank 2 is the bank on the driver's side. The one code refers to catalyst efficiency , but the repeated codes for the same cyl could be indicative of more than one problem. I wouldn't go replacing parts based on the possible causes presented here without confirming exactly which of the possibles are the problem.
Some possibilities could include the o2 sensors for bank 2 , the converter for that bank, and the O2 sensor after that converter,or maybe a problem with the variable valve timing system. I believe there is more here than you might want to handle alone.

 

So it's been a few weeks, but I thought I should give you all an update. The problem WAS the catalytic converter on the driver's side. I got in with a mechanic and he was troubleshooting the plugs, coils, and fuel injectors. They couldn't figure it out until he took it for a drive. Came back and dropped the cat. It was completely demolished inside. It came all apart and there was virtually no flow through. He put a new one on in the morning and that was it. It's been running great since. Of course it cost me twice as much since I already had replaced everything else first, but hey, I'm back on the road. Thanks for all the help.