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.


https://dl.dropboxusercontent.com/u/737 ... %20PM.xlsx

https://dl.dropboxusercontent.com/u/737 ... 8%20PM.xls

or is simply a faulty 02 sensor

Check wires and for spark at each cylinder
Test the fuel pump pressure

Perhaps a new fuel pump is all that is needed?

Telcoman

telcoman wrote:Check wires and for spark at each cylinder
Test the fuel pump pressure

Perhaps a new fuel pump is all that is needed?

Telcoman

going to check the resistance at each coil this weekend, but if there was a bad spark I would expect a code to be fired which turns on the SEL.

If it were the fuel pump wouldn't it be acting up above 800RPM?

When is the last time your spark plugs were replaced or checked?

Pull them out and check that the gaps are within spec.

ArmedAviator wrote:When is the last time your spark plugs were replaced or checked?

Pull them out and check that the gaps are within spec.

they were replaced like 4 months ago to resolve a miss on acceleration(oem iridium plugs)
coincidentally this started to happen right after the plug change

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 irratic 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???? Any solution out there?

Acagrill wrote: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 irratic 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???? Any solution out there?

Have you or your garage ever consulted the FSM and followed the troubleshooting steps?

http://www.nicoclub.com/FSM/G35/Sedan/2 ... dan/ec.pdf

See page EC-301

Telcoman

Thanks Telcom,
The issue started about 2 weeks ago. The garage told me the monitor said that the #3 cylinder was misfiring. So I started trying the solution on my own and haven't consulted the FSM. I'll probably get a monitor this week so I can do some diagnosis and go from there.

My problem has been fixed.

after several weeks the car finally threw a code pointing to #3 cylinder. took the #3 coil and put it on the #4 cylinder, took #3 plug and put it on #2 cylinder.

drove with the miss for several more weeks until it threw a code pointing to #4 cylinder, based on what I did above I replaced the coil and all is fine.

Note: the OHM readings on #2,#3, #4 coils were all the same, the gaps and ohm readings for all three plugs were all the same too.