CAR: 2005 G35 sedan with 159K miles

We've been plagued with an intermittent miss at idle whilst in gear at stop lights.

There are no codes being thrown, and is not present at any other speeds.

when it first happened, the "hiccup" was just a couple of times at each stop light. Then it progressed to several hiccups per stop light.

we tried Chevron's fuel injector cleaner and for about a tank, maybe two. The problem went down to one hiccup per day rather than per stop light.

the problem came back and we tried B-12 injector cleaner, and that only got marginally better.

The problem is way more prevalent whilst in D or R, and barely noticeable in N or P.

I vacillate between the replacement of all injectors to an issue with the torque converter. I have nixed the torque converter as it can happen in N and P.

thoughts? Please help, too embarrassing driving like this.The G is not a beater car, so shouldn't run like one. :-(

 

I did a capture of the G35 at idle whilst missing and did the same for my same year 350z...maybe someone could interpret the data....to me I believe bank 1 is the problem side, but have no clue if it is ignition or injectors.

G35 missing capture with some charts

350z capture and comparison on tabpage 3


one of the things I noticed in the comparison chart is that the timing on the g35 is going to 13 degrees(from 15), whilst the 350z starts at 15 (within specs) and briefly goes to 16, never going below 15 . Both are within specs (which states 15 +/- 5 degrees).....at idle what would make the spark advance go down to 13?

 

Update - Still not fixed
My wife called me last week with glee, the car finally threw a code and turned on the SEL for a bit. The codes were P0300 and P0303....At least now I had something to go on.

being that it reported cylinder #3 misfire, I tackled into looking at it.

Took the coil off and the took out the spark plug. checked the ohms between the coil's terminals and compared the readings to the manual's expected numbers and it was within spec. I pulled out coil #2 and Coil#4 to do the ohm check there too to see if #3 coil was different. the test between pins 1 -2 were all infinity for all three coils

changing the range of the meter to Kohm I got very close numbers
#2 kOhm between pin 1 and 2 = 1.733
#3 Kohm between pin 1 and 2 = 1.619 (the reported misfired cylinder)
#4 Kohm between pin 1 and 2 = 1.644

the remaining tests between 1 -3, and 2-3 were all as per specs = inifinity

I re-gapped the three plugs to .043 inches, they were all a little narrower like .041 -.042

I moved #3 plug to #2 cylinder and moved #3 coil to #4 cylinder....#3 cylinder has #4 coil with #2 plug

warmed up the car to about 180 degrees and thought the problem was fixed until I took it for a longer drive, the issue is the same(water coollant at 190 degrees)...and not throwing a code yet. I hope the code appears and tells me it is on the driver's side rather than the passenger side.

I have taken another log when the car is missing and will compare the results to the previous log and post the results to dropbox.

 

UPDATE - FIxed!!

wow it has been a while, drove the car for weeks with it missing after moving the components to the other side, with NO CODES THROWN. One time it threw a code, but it was just Multi Cylinder MisFire, not helpful.

Yesterday it threw a code P0304 !! which means that #4 cylinder mis-fired and based on what I did above, points to a coil.

I replaced the #4 coil with a brand new unit and had the wife go to Sam's Club and the verdict was Fixed!!

Unfortunately I can't return the unused injectors, but I guess once this is fixed I'll go ahead and replace the injectors...can't hurt.

what a wild goose chase with the car running better with injector cleaner added to a few tanks..


BTW looking at the logs once the components were moved, didn't really show a telltale sign that the problem moved to the drivers' side...
only the CEL codes going from P0303 to P0304 was helpful....but that took a very long while with the car still missing at idle.

 

Thanks for reporting back. This would've drove me bonkers.

 

I'm, having the same issue. G35 with 220,000 miles. After problem started, I have: changed spark plugs, changed air filter and cleaned mass air flow sensor, cleaned throttle body with Sea Foam and put 2 bottles in the fuel when the low fuel light came on to maybe clean injectors. Garage told me the #3 cylinder isn't firing so I changed the #3 cylinder coil (didn't fix problem). looked and listened for vacuum leak. Car drives great, has no hesitation, good power, idles at 650 rpm, just seems like an erratic misfire at idle in drive like when your sitting at a stop light. Take my foot off the brake and no problem. I tried at stop lights, foot on break and bringing idle by gas pedal to 800 and problem doesn't happen????

I'll try your solution if I can figure out exactly what you did. But I already replace the #3 coil which I believe is what you ended up doing after putting it on the #4 cylinder.

 

the worse case scenario is that there is something wrong with the little wires going to the #3 coil....but I highly doubt that.


Since you replaced the coil and the plugs, the only thing I can think of is that it is an injector problem.


on our cars there is no way to easily test those thanks to the stupid plenum .


when you replaced the coil though....did the car throw a code (SEL Service Engine Light)? Definitely go to the brick/mortar stores and get a code reader.


If you have an IPhone buy DashCommand and the ODB2 port adapter Elm327 WiFi (only the wifi version works with IPhone) it tells you so much as to what is going on. In my case it didn't help as it was a coil.


it is conceivable that a different coil is acting up, but is not throwing a code yet.


Keep us posted

 

So I bought the ODB2 ELM327 Wifi adapter. Then for my i-phone found OBD Fusion app which was a $10 mistake. It didn't work as it only showed the voltage and what I believe was bad diagnostic codes.So after a few weeks and the car getting worse to the point that I could really drive it, I bought the Dash Command that cfauvel recommended and wala all the gauges worked. It also showed me a P0306 code because the car was finally throwing off a code. For weeks it would just misfire sitting at red lights without throwing codes. So I took the #3 new coil (read above) off which I replaced and put it on the #6 position. The P0306 went away and the car now was drivable but with what I would call the regular misfire since its been over 2 months trying to fix. I decided to bring it to another garage last Monday but they couldn't find a problem because again there were no codes. However he did speak with his service manager friend over at a dealership and they said with cars of my mileage 225,000 they would replace all the coils and clean the injectors. So I know Infiniti coils are $150 each and aftermarket are $55-$75 each. Either way it's a lot of money for 5 of them. So I did what I could afford. Ebay 6 new coils for $85 total. My only concern of course is the quality. Bought last Thursday, received Saturday, installed today Sunday. Drove the car a bit today and the misfire is gone. Hopefully it was last for awhile. Anyhow if it comes back I may be able to diagnosis it better if 1 of the coils goes bad. Hopefully you guys won't give me a lot of heat for buying the cheap coils. It's not my first choice but what I could afford and was a cheap shot to diagnosis the problem, Many thanks to the forum and members for their help.

 

I've had good luck with duralast replacement parts. I think you will be okay. Glad you got it fixed.

 

First thing I always check is for vacuum leak. When I read the title before the post that's what first came to mind. If you have e checked the basics ignore. I'm chasing down a TPS code but doing all the free stuff first.

As far as parts. Look at RockAuto. They list there parts as economy, OEM replacement or performance in 2-3 categories. OEM is great but usually OEM replacements are just as good. AC Delco makes a **** ton of OEM parts for American cars and nothing on our car but there parts are top notch. Nissan/Infiniti and other manufacturers make deals for certain parts on cars, doesn't mean it's always the best. Just don't get the cheapest part and don't get the most expensive. But look at the site I mentioned. Parts will be listed as new, OEM, or reman. Prices are half of what you pay locally.

 

Digging up an old thread but it brought up something in mind.

All my lights work fine.

Auto works from dusk til Dawn
Brights, fogs, everything works
The button that looks like just fogfights before the headlights are on won't turn any lights on. I thought these would have been DRLs but I have an American car. So the spot other than headlights and auto on my **** does nothing. When headlights are on I can turn fogfights on or off. They can't be turned on when the headlights are off?

 

No they can't, sorry.

 

Figured. Everything car I've owned had this option. So I imagine a relay and some wire tapping can fix this I'm assuming.

 

I hear you and you can probably make it work.