Hey guys, I am baffled by the predicament that I am in and I'm looking for some help/guidance.

2012 G37 Journey Sedan, Automatic, Stock with 130,000miles; Muffler Delete; Changed spark plugs last year with Denso OEMs.

My car has functioned flawlessly since I've owned it. It ran perfectly on Sunday and when I started it up on Monday, it ran horribly. Used the OBD2 scanner and got the P0300 random cylinder misfire.

Took it to the local shop where my fiancee and I always take our cars. After some testing, they discover that the 1/3/5 cylinders(Passenger side) are not firing. Oil is changed, ignition coils and spark plugs are replaced, no change. Test a new O2 sensor, no change.

They take it to the Nissan Dealer. The dealer suggests new fuel injectors($420) AND an ECM reflash ($1,500). We decide to have my guys swap out the fuel injectors at a cheaper price, no change. They said that they were able to reflash it(I'll have to clairfy if they flashed the ECM or just Reset it), but still nothing.

So now I'm in a bit of a dilemma. It looks like the ECM may be faulty. If that's the case, would replacing it be as simple as purchasing a new/used ECM and reflashing it?

Are there any other suggestions you guys have? Am I going crazy? lol

I sincerely appreciate any help that you can provide!

 

Welcome to the site. Sadly, I have nothing to offer but greetings.

 

There have been a few cases on this forum and the 370z forums of some of us needing an ECU because of this. Yes, it could happen. Yes, you could need a new ECU. In short your ECU is not telling the cylinder to fire. This is the first I have heard of three cylinders happening at once which makes me apprehensive to say it is the true issue.

In my case I just bought a used ECU of the same year and model as mine of ebay for like $70. Took it to the dealership and had them flash the new ECU to the TCU and key fob. They did it for free. The hard part for me was getting a new ECUTek license and getting my tune switched over so I could drive the new car on the new ECU. They also worked out a deal with me because it truly was an issue, and I thank ECUTek for having good customer relations on that.

So, my advice: buy a ECU off ebay that fits your car. Take it to the dealership. Ask them nicely to swap it over and flash over your ECU, TCU, and FOB to all talk to each other. You already handed them a ton of money and got nothing to show for it, so they should do it for free.

Welcome to the forum and good luck!


Oh, though I have found no real connection between the four of us that have had this issue, I have realized each of use have had some type of exhaust work that involved arc-welding or arc-cutting. I have wondered if because work was done with high amp welding equipment with the battery still connected if it somehow fired the ECU. Just conspiracy theory food for thought. On mine it would happen ever so often over 3 months before it just was constant.

 

If an engine bank is out, I'd imagine something common to that side of the engine would be at fault¿?

The ECU controls many things, I'd expect misfires on all 6 cyl's if that was the issue.

 

The ECU controls each coil on a separate circuit on its board. If one or three of the circuits short it will cause a misfire because it will not be able to get the signal to the coil. The ECU would not know its doing wrong because the signal goes from the processor to a series of circuits to the wire to the coil. You can take your ECU apart and easily follow the path on the board (back trace from each injector pin on the ECU, they are all six next to each other). The misfire is detected by the sensors in the engine and reported back as a general misfire if it can't nail down the problem cylinder(s) and why. Since it sees it is sending the coil signal, the injector pulse, and everything else seems fine it drops the P0300 code.

I do find it odd that an entire bank is off line, but I was just reporting what I found when a similar thing happened to my self, and how i fixed it permanently, as did a few other with the same problem.

 

I just got this car, but my V6 Audi Had ignition control modules, 2, one for each bank. Although rare, they did go out.

 

I had a similar issue and was getting a P0300 code. Ended up being a ground wire loose on the front of the timing cover. Car was hesitating a lot and ended up running rich over time and clogging up my cats, not fun at all.

 

I have the same issue on my Dodge Dakota replace the ecm and now 88 miles later went from misfire 1 3 5 to just misfire 5 and trying to figure out what to do next.

 

Daniel more than likely you have a crank sensor or wiring harness issue their buddy.