Hello org'ers, my 5.5 has been giving me a ton of grief.

I picked it up with a p0300 from the previous owner thinking that I would just need to replace plugs or at most coilpacks just like my old 4th gens and I did just that. The old plugs were severely worn and all coil packs were aftermarket.

So in went NGK Coppers and 6 new OEM coils. Misfire still persisted and p0300 was still present. Now the misfire is mostly present at idle and its pretty bad. While driving though, it drives pretty well. Ill ocasionally get a p0302 so I replaced the new NGK plug with a brand new NGK plug today and a known good coilpack and the misfire is still there.

Ive also replaces injector in cylinder 2, fuel pump, gutted my pre-cats, 6th gen valve covers. I just don't know what to do anymore. Any help would be appreciated.

 

Try cleaning the IVT solenoids. Spray the absolute **** out of them with carb cleaner. Hell, soak those bastards for a while.
I've seen those throw p0300, but not the IVT code (until it got really bad). And symptoms were the same, misfire at idle that cleared up when driving.

What condition were the cats in?

 

Surprisingly the cats weren't to bad but had signs of some clogging according to my buddy that did the job.

Im sorry but i searched IVT and didn't find anything as far as pics go. Can you provide a link to it?

 

It's not your plugs or coils. It's something common to all cylinders. Perhaps a vacuum leak; check your hoses for cracks and tightness. Check/clean your MAF. And read this thread: https://maxima.org/forums/5th-genera...e-misfire.html - from beginning to end.

 

Its a either a vac leak OR you got a dead cylinder with low compression.

 

Since the ECU check things via electrical circuits, I kind of doubt that it would be able to tell that a cylinder had no compression and throw a code.

 

I know this sounds crazy, but my p0300 was troubleshot down to a faulty master window switch drawing too much power at idle. Car would flash the SES at stoplights or sitting for long peroids. When I bought the car the switches were a little buggy, and wouldnt always work, replaced master window switch and the p0300 dissapeared forever. I never changed anything else so there was no way that the window switch wasn't the problem...again crazy, but just some tiny input

 

What the fark? I have a spare one so its worth a shot lol. My money is on compression though. I'll post results tomorrow

Some bad news, the motor is unfortunately toast. Did a compression test on the car and heres what I found.
150 150 140
90 90 90

 

You need a new timing chain. You probably ran the motor low on oil and it skipped a tooth.

 

Misfires suck man. You should have done a compression test before buying the car. I learned that the hard way when I bought my first used car from an owner. Hopefully the buying price wasn't too high.

 

Don't know how replacing a timing chain would bring back compression. But yes when I bought the car I did an oil change the next day and less than 2 qts came out. I the front vc was leaking and the does burn a lot of oil

I bought the car for 1800. The car ran and drove great and had a p0300 code. Though it would just need new plugs and coils. It's okay though I have a spare motor in my garage which will get swapped in the summer

 

Hopefully the compression on the garage motor is still good.

 

Crusher is right. Replacing the timing chain on its own would not fix your compression problem; but replacing the timing chain AND adjusting timing on bank 2 to correct the slip should.