Always good to reach out on more than 1 platform. I'm sure that one of these guys, maybe one of this forum's moderators, would love to do that with you. Maybe you can cross pollinate the 2 with tech information.
I looked into my toy bag. I'm hoping that I have the right combination of extensions and spark plug sockets to do the job. That big piece is a deep well spark plug socket, for engines like Transit Connect with deep wells & coil over plug. I've got a couple of different swivel spark plug sockets in different styles. A few extensions, a swivel, and a finger spinner. I've got a couple of spark plug sockets without the swivel, in 3/8" & 1/2" drives. 1/2" in case I need the torque to break it free.
Not so crazy. Some people do that. Some people clean the spark plugs also.
I noticed that the /r/FordTransitConnect subreddit was abandoned - no moderators and no activity for a year. So, I requested ownership of it. I updated the 'about' info to point here to this forum as the primary place to talk about Transit Connects.
I'm open to doing more with that subreddit and I'd love if someone else would be a moderator with me. I'll probably post stuff there from time to time as I find relevant things on the web.
Anyway, just wanted to throw that out there. There's a lot of people on reddit so I imagine some TC enthusiasts will see it.
OEM plugs are .50 gap. Your new plugs are .52. Rule that out.
As I was looking, I see that Autolite plugs are $4, and there is a $3 rebate.
I found this online:
Low Fuel Pressure– If there isn’t enough fuel getting to the engine, this will cause combustion to be less than optimal. Diagnosing low fuel pressure can be tricky. Typically, if you do have low fuel pressure, the vehicle will act fine when it doesn’t need a lot of fuel. But, it’ll sputter and act like it’s going to die at speed or under heavy acceleration. Here’s some information on how to tell if you have a bad fuel filter.
Vacuum leak– If your Focus has a vacuum leak, it can be very difficult for it to get the right air/fuel mixture. This will cause the cylinders to misfire and it’ll throw the P0300. Also, since a vacuum leak almost always affects each cylinder the same, you’ll typically get P0300 with it and not any cylinder specific misfire codes. Here’s a great article from Popular Mechanics on how to detect a vacuum leak. It’s easy (and kind of fun) to chase one down. Popular Mechanics: How to find a vacuum leak.
EGR Problems– If the EGR system is not able to recycle the engine gasses right, it’ll throw P0300.
Ignition Problems– Bad plug wires (if equipped), bad coil packs, and spark plugs can cause misfires to occur. This isn’t higher on the list because typically you’ll get a misfire in one cylinder specifically, and not a P0300 only. If you got a P302 or something similar with the P0300, it may be a good idea to check and see if there is any damage or failure from your ignition components. Here’s how to test a coil pack, how to tell if a spark plug is bad (video), and how to test plug wires (video).
Cam or Crank Sensors– This one is very unlikely, but it does happen. If the ECU is not getting the right signal from these sensors, the vehicles timing is not going to sync up and it’ll misfire.
Low Compression– If you have a leaking head gasket, bent valve, cracked head, etc.. that would cause compression to not be as high as it should, you’re going to get P0300. You should also feel the vehicle is down on power as well.
Most Common P0300 Fixes
A lot of the time, P0300 is going to be fixed by something obvious, such as an EGR leak. When it’s not glaringly obvious what is wrong, a tune up is a great place to start.