Ok guys here is the back story...

One day I was driving the car and it randomly started making this noise (felt like the exhaust was farting) and the engine was struggling.

I hooked up the code reader and found it was P0300 error. (random misfire in multiple cylinders)

I searched this site and found that the cheapest solution was changing spark plugs, so I looked up the DIY for spark plugs and changed # 2,4,6. The passenger side (1,3,5) were impossible to change so I didn't even bother.

When I opened # 2, I found some oil on the plug and replaced it with NGK regular plug
# 4: the plug was submerged in oil!! and the coil pack was full of oil. I took out as much oil as possible and changed it with NGK platinum plug
# 6: same as # 4 a LOT of oil. Cleaned it up and replaced it with NGK platinum plug

Put everything back together and voila car ran better than it did before the problem! I was patting myself in the back and telling off my friends on how I have a bright future as an auto mechanic if I ever were to get laid off... blah blah blah

Then yesterday, we went on a 1+hr drive to upstate NY (hilly road) and on our way back the CEL started flashing and that problem came back! Car started struggling, noise from exhaust, etc...

Got home, saw that now it was P0304. I was like piece of cake, I will take it out, if there is oil then clean it up and boom should be back in business...

but nope

I changed the NGK platinum with a regular NGK plug. no go
I swapped coil pack with cylinder # 2. no go
I cleaned the NGK platinum and replaced it back. no go

What else should I try?

Also judging by the amount of oil in my plugs I am assuming I have to change that 'cover' forget whats its called as well, yea?

 

Time to change your valve covers.

The oil Is probably getting into the COPs and causing connection issues or causing them to fail. Your spark plugs are probably ok (just clean the oil off)

 

I hate to sound like a newb but what's a COP? Are you talking about the coil pack? I already switched #2 and #4's coil pack and the error code still shows P0304 and cylinder 2 works fine

 

Yes, coil on pack.


When you swap them, are you erasing the codes and then waiting for them to come back before retesting?

 

Well I have the negative cable off the battery before I swap the plugs so the code automatically gets erased. Regardless, when I start the car I don't even have to wait for the code to know whether or not the problem exists.

But I will try erasing the code one more time to see if P0304 changes to P0302. I doubt it though.

 

I always though it was 'Coil On Plug' ?

 

You are right.

I've gotten so used to using the term COP I forgot the real meaning

 

So then you definitely have an issue with cylinder #4. (middle cylinder drivers side)

So three things

Spark - check the coil and plug. Sounds like youve done this

Fuel - bad injector. Don't really have an easy solution to check this

Compression test to determine if you popped a head gasket.

 

Any idea how to do # 2 and 3? How can I perform a compression test? Is it a cheap machine I can buy or any mechanic should be able to do it?

Another thing... when this problem first happened the oil was only limited to the space between the plug and the COP

Now the oil seems to settle on the tip of the plug! What can cause that?

 

Compression check is easy...but that might not be your issue. But if troubleshooting gets you no where, you will want to check compression of the cylinders.

Oil pooling in the spark plug wells is caused by the valve cover leaking oil. To fix, you need a new valve cover. While not a condictior, oil in the COP could be an issue.

How quickly dpes the oil reach that level? If you clean out the plug well, and put a clean plug and COP in, does it run fine?

 

Thats the problem. When I first got the P0300 error, I replaced plugs 2/4/6. All of which had oil in them. Especially # 4 and 6. I cleaned up the oil as much as I could, replaced the plugs and the car ran perfectly fine.

Then when I went on a 1hr trip up north on a hilly parkway, on my way back the misfires came back! I figured the oil must be blocking the COP and plug again but when I checked there was very little oil. I don't think its oil in COP because now I only get P0304 code and that is after replacing the plug one more time and swapping COP with plug # 2

It is definitely a leaky valve cover gasket, but why am I still getting a misfire? I already cleaned up the oil.

 

Hmm...this one has me thinking.

Usually, to check spark, i'll remove the plug, plug it into the COP and lay it on the head to ground it. Then i'll put another plug in to seal the chamber up and start the engine. You should see a bright spark at the end of the plug flickering away. Did a lot of oil go inside the chamber? How does the tip of the plug look? clean? or is it fouled?

I don't suspect fuel because the problem fixed itself and then came back. Same with compression.

So i def think it's spark..but kinda puzzled as to why

 

I am not sure how much oil went in the chamber, I thought the plug should've blocked it, no?

The new plug that I had just put it a couple of weeks ago was black and covered in I guess carbon? And on top of that it was wet. So I replaced it again with a regular NGK plug but no go and then cleaned up the dark part the best I could and still a no go.

BTW I did switch the coil packs for # 2 and 4 and never switched them back. I thought they are all generic and can be used interchangeably but then I read another thread regarding this issue and someone said that the problem was due to switched coil packs?

 

Do you think while unplugging the wires that go into the COPs, I might have damaged the one for # 4?

Do you know how I can go about checking if any current is coming through that wire??

 

I think cops are generic. If they weren't you'd have a misfire on two cylinders when you swap. Trying swapping 4 with 6 and see of the code follows or stays p0304

How I would test it? I'd pull the COP off. Stick a plug in the end, ground the plug on something metal and start the engine. You'd see the spark firing away.

However I've done this on older engines..so trying to see if this safe on a new engine.

But it is possible the wiring to the cop is damaged as well