I got a code on my 2012 nissan maxima that is had a p0302 code, swapped the coil from cylinder 6 and still got the code on cylinder 2. So i purchased new spark plugs and put them in on all 3 front side (2,4,6) cylinders. Now with new spark plugs, I get code p0302 and also p0300 random misfire. I replaced the coils on all front 3 cylinders and the spark plugs and still get the same 2 codes. I tried putting back the original spark plugs and the original coils and I get the 2 codes. Any ideas?

 

How do the plugs and coils look? Any oil? Sometimes, the seal on the oil covers leak and can cause the symptoms you describe. Also take a close look at the wiring for any "critter damage" You didnt mention what you used for coil and plug replacements. Let us know a bit more and we can see what more advice we can offer.

 

So i've only done the front 3 spark plugs and coils. I used the following spark plugs and the coils

https://shop.advanceautoparts.com/p/ngk/12102020-P

https://shop.advanceautoparts.com/p/...earchTerm=coil

and i've attached what the spark plugs looked like when i removed them

 

Let the engine cool down and pull those plugs out that you replaced. If they are covered in oil, like the ones you replaced, then you have oil control ring, or valve seal, issues.

If they are fine, then check the gap on the plugs your put into the car. They should be 0.44 or 0.43.

 

I agree with TDGrant you have a lot of oil on the plugs. I would not gap iridium plugs the electrode can break. I also not sure about the advance coils either. Modern cars like these are picky AF about parts. I would get some Seafoam, BG44k or the likes and put it in the tank to clean up the combustion chambers and rings. How many miles on this Max?

 

this is what it looks like with the new spark plugs, ran for 30 mins. I don’t see as much oil as the old ones had. Still getting error codes the maxima has 132k miles on it.

 

They Look Fine.. put them back.

What you need to look at closely, is the Coil pack Connectors.. Make sure that the wiring is not Broken.. or showing any naked wires. Or that you have not bent the Connectors inside the Coil while plugging them in.

 

Here’s an eBay plugs buy - for our Gen

https://www.ebay.com/itm/40367805499...mis&media=COPY

 

The tub seal is leaking oil and causing oil to foul out the plugs.

the surgery shouldn’t be bad - I did the tubs in my tundra…..

here’s the fix


replace the tubs!!!! If you don’t, the new plugs will be fouled again.

Note: I watched the video after posted Just buy the tub case. I will check around online for any good source.

 

Here a source

https://www.ebay.com/itm/32311248360...mis&media=COPY





call their customers service and make sure they tell you which one you will need. If no help from them, call a source/stealership to confirm the correct part.


https://www.nissanpartsplus.com/sear...tr=Valve+cover

 

put some anti-seize grease on the threads..

 

And if you haven't seen any evidence of scoring or burn marks you may just have some defective or clogged injectors. Check the tubes for any evidence of burn marks or tracking. If they exist, even with new coil packs, you can still get more arcing as well. It really is easier just to replace the oil cover than discreet tube seals and if you did have any carbon tracking, a lot easier to see.

 

yup. The stealership don’t sell the seals, only the case…

 

It ended up being the coils. It's weird though, i put the new ones in and it immediately started running better but I can't seem to clear the error code from my scanner, tried erasing but it still comes back but I can see it is running much better no missing.

 

You really ought to replace those rear plugs and packs too. I know it is a pain in the rear, but if the fronts are any indication, you probably have some issues in the rear as well. And if you aren't running Tier 1 gasoline you may want to run a couple of fuel cycles with some injector cleaner. With the p0300 still occurring, cleaning the injectors and replacing the rear plugs as a minimum should get you back to full no-error condition. Granted I run mainly highway miles but my plugs after 150,000 Miles look almost new. Yours, not so much. Also Denso recommends not to gap the plugs (they are pre-gapped.) But it is your ride.

 

I plan to, thanks for the help

 

note. If you have oil on the plugs, this will repeat itself and will have to repeat process.