Impossible connector clip and cylinder 4 misfire

[jpasquini]

Have had a P0304 Cylinder 4 Misfire code for about a year now, but its only happened occasionally. I've changed out all the spark plugs and the ignition coil, but no good. Now suddenly after an oil change yesterday, the engine light appears to be flashing 90% of the time, and I can feel the engine a bit rough.
Enough to cancel the Christmas trip.
So here I am, still, with a Cylinder 4 Misfire.

I'm assuming that the Cylinder 4 would mean the 4th spark plug counting from the front of the engine back, which I replaced a second time yesterday (See attached pic I'm referring to). No good.
I found this video:



Which talks about rusted sockets inside the fuel injector harness, which could possibly be the problem.
But I can't get the blinking harness clip unplugged!
Its welded together fast.

There's a ridiculous red clip that flips sideways, which I pried to the left, but still the clip won't release.
I've since broken the tab on the front, and when I tried to pry it open, broke off a bit of the side.
So I thought I'd find someone to ask before I struggled further.
Aside from boiling the designers of Jeep clips in motor oil like they deserve, does anyone know how to open this puzzle clip? Its not the first 'creative' Jeep connector clip I've encountered by far.

2002 Jeep Wrangler Sahara 4.0L 6 cyl

 

[Lou]

You have the red lock sufficiently released. Looks like you broke the piece that you need to push on to disconnect the connector. If you carefully stick a pocket screwdriver or small pick up and gently pry out, you should be able to free the detent.

FYI jeep nor chrysler designed that connector. That is one of the most common automotive connectors used.

I didn’t watch your video but the title says it’s for a JK which is a completely different engine.

 

[jpasquini]

I've tried prying a screwdriver in where you are indicating, but Im afraid its going to break the plastic housing.
I'm aware its not the exact same vehicle/make/model. But I've had to broaden my search in trying to find out the cause of this problem.
As far as the clips, yes I've had the Jeep since 2002 which is about 18 years now. I am still coming across clips I can't figure out how to open. Such as this one today. I think I have a right to be annoyed by them at this point! lol

 

[Lou]

If you have a single cylinder misfire and suspect it is a wiring issue to a fuel injector, the wire you would be worried about doesn’t go through that connector. I would leave that guy alone before you break it any further.

 

[Lou]

You can test the fuel injector wiring with a noid light, however, I doubt that is your issue. If I was troubleshooting it I would take a good look at the plugs and while I was in there I would do a cylinder leakdown test. If that checked out I’d swap fuel injector 3 with 4 and see if it follows.

So you changed the plugs a year ago, what plugs did you use and if possible could you pull #4 and post up a picture of it?

 

[jpasquini]

Well that's the question. Is not spark plug #4, for cylinder #4 the 4th counting back when facing from the front of the engine?
I'm a bit put off by the "firing order" as shown in the attachment.
Anyway, that was the one I replaced with brand new yesterday.
I had already replaced all of the plugs and the coil last year, but still was getting the P0304 intermittently.
Now for some reason, its almost constant as of yesterday. With check engine light solid when its running smooth, and blinking when its running rough.