Plug it where the sun don't shine

My Subaru was sometimes chugging and hesitating and sometimes felt like I had no power. My check engine light was going on and off and then remains solid. Originally it was happening the odd time, but lately it was more frequent. My OBD-II computer was telling me two codes.
The first code was for the knock sensor.

And the other code I was getting was for a CYL 4 misfire.
I figured the misfiring was causing the knock sensor to go off.

So I check on line and the forums say to replace plugs, coil pack or injector is burnt out, or something I forget. Start with the plugs since they are the cheapest.

Then there's the ignition wires but I checked those and those are still fairly new and in good condition. Not hard and brittle, no cracks. So they are fine. And the coil pack is the most expensive part.



For $9.99 at Part Source you can get a pair of NGK plugs. If it works then it's $20 bucks and I'm done.
If not I have to go and try the next thing.

So for today, the day after April fools I give it a go. Never having done this before I reviewed the service manual (not the OWNERs manual, that's got nothing useful in it) first.

Gotta remove the battery. Then the washer reservoir. Then I can get at all the plugs. Of course the plug that might be causing me the problem is the hardest to get at. That's how they always do it. It's by design. So you can be swearing to the skies about why the hell they designed it this way. Obviously the engineer or designer, doesn't service his friggin car.

But I got them out. Phew. So now I have an undriveable car. I can't sit around having a beer. I won't be able to get something to eat.

Just by visual appearance old ones were pretty worn out. It's supposed to a little needle like thing there, not a rounded nub. And that gap is supposed to be 1 to 1.1 mm. These were a bit more than that.

I have the images in order from cylinder 1 thru 4. And 4 was misfiring.
This is plug number 4. You can see it's by far the most worn down. Hopefully this solves my problem and the misfiring goes away.


I did notice the knock sensor code came on. So maybe it's malfunctioning and needs replacing.

But I got it done. By myself. If I can do it. Anyone can. You know if you took this to the dealer to get done they would stick you with a bill somewhere between $200 and $300. And they'd charged you $17.99 per plug. Because it's an OEM plug. And just doing the diagnostic to get the code. Is a $90.00 up the butt charge. And then they'll say your handbrake needs tightening or something just to get more of their hand into your pocket.

This job cost me $20.00 + tax.
The dealer can put that OEM plug where the sun don't shine.