06 Mountaineer 4.6l V8 Cylinder 1 Misfire
 

I have had this mountaineer for about 3 years now and love it. I have had a few problems but most of them were just regular maintenance things I needed to take care of as things went bad or whatever. I now have the P0301 code (I think that's the number) which is a cylinder 1 misfire. Here is some info I want to mention: It is winter in Michigan and the other day, we had a bit of a warmup after endless freezing temps up to around 45 degrees. So on that day, I changed the oil, as well as the air filter as the old one looked terrible and they finally had a new one in stock. This misfire happened within 2-3 days of the new filter and oil change. And I only drove maybe 25-30 miles after as well. I also just changed all the spark plugs and ignition coils mid-fall 2021. And soon after I changed the MAF sensor. I suppose any one of the new things I put on (besides the air filter) could be faulty. But I just have no idea. I am not a car person in the slightest, but it's been awesome doing all of this work myself, with a little help from my dad. If anyone has any suggestions, tips, or anything that could help, it would be greatly appreciated! Thanks in advance!

I have more information to add. My check engine light has been on for most of the time since I got the Mountaineer, but that was never a problem. It's only flashed when I had a misfire. And I made sure to not drive with the misfire and fix it ASAP. Now, when I had an Auto Zone scan it for me a little over 2 years ago, they said I needed a new catalytic converter. I understand that eventually that may need to be replaced, but it also seems that if it was completely bad and not functioning, there would be very noticeable problems. The code I've always gotten is something like "catalyst system below efficiency threshold bank 1". It seems a lot of the parts that eventually go bad on vehicles are going bad on my Mountaineer. So I am considering buying all new o2 sensors and trying that. I do also have an exhaust leak. You can't really hear it, but I can tell there is one. Just, the vehicle sounds fine. I am not going to start throwing parts at it, as I do have an uncle who is a mechanic. So worst case I bring it to him (which isn't bad, he's just always busy) but I would like to be able to fix it myself! I know this is a lot, and hopefully someone has something to help out with all of it. Again, thanks!