For what it is worth, my Mom's saturn had a marginally similar issue and it was a broken engine coolant temperature sensor. the sensor was bolted into the engine block coolant chamber and had split open so the ecu couldn't tell what temp the engine was at. If I stepped on the gas too fast or too slow, the engine would stutter (almost die) then rev up fast to where it should be. the symptom only was evident when starting from idle or a stop. didn't matter if it was in park or drive. I can't remember if the car cell warning was triggered. Again, this may not help but who knows.

 

ok i dont know if this might help you guys but sure made my car run like new and smooth as hell
i bought my car 2 weeks ago ... the night i got it the car starts to sputter, sometimes wanted to stall ... id be cruising and it would sputter every mile or so ... anyways took it to the dealer ... found out that previous owner rarely did oil changes ... and it had damaged the pcv? valves (cant remember the exact name) oil runs thru them and when dirty oil runs thru them they start to get damaged and build up pressure ... the dealer replaced it ... did an oil change, put new filters in ... now my car runs like brand new ... i only have 43k miles btw

hope that helps ..

oh and they also did a software update on the cam sensor

 

^ +1 something you should check out. these pcv valves hould not cost more than $10-15.

Read post 12 by da mayor

1st gen pcv valve DIY shouldnt be much different. Symptoms usually are sputtering, burning oil, rough idle/rpms.

 

Just found this thread and my wife's 07 G35X (55k miles) is doing a similar thing. Around 35 mph and about 2 minutes into the start of the daily commute the car stutters. Almost feels like the fuel was instantaneously turn off then back on. No codes on my scanner. No MIL light.

Anyways, it happens when the car has been sitting for a while. Has not happened yet during the day when you go out to lunch, for example. Only morning after car has sat.

The mornings have been a lot colder than the days around New England lately. And I drove the car after letting it sit outside all night around 46F degrees. Sure enough around 2 minutes in at 35 mph it stuttered! You can floor it and it is fine, just happens when crusing under almost no load. Tried gas cleaner a few tanks, nothing.

Will change the PCV and see it it goes away. Also bought plugs just in case. May try electronic cleaner on the MAS's, that worked on my German car before.

The car has Stillen short intakes, which went in when the car was new. Oil is Mobil 1. Never had any issues with the car until now.

Thanks for any help,
Steve

 

every '07 g35 i know does this "morning sputter" and so do HR 350Z '07-'08.

check this thread, currently problem is not solved, but it comes from VTC solenoids, but no one tried to replace them by now:

http://my350z.com/forum/vq35hr/30787...g-warm-up.html

 

I've been noticing the same problem: upon start up and at idle. On start up, my rpms will drop below 1 and sound/feel like it's going to die before returning to normal. On idle, it does same thing if I rev my engine. I have an 08 6MT.

Someone just posted a thread about some service bulletin being released recently on this issue:
https://g35driver.com/forums/g35-sed...-rpm-idle.html

 

Did you really need to post this three times?

 

Needed input and thought I could help if no one was aware of the service bulletin. But thanks for noticing.

 

No problem. Hopefully you noticed I responded to you in the other two threads too.

 

Just bought my '08 g35 auto trans a week ago. No problems until I disconnected the battery for 20 minutes. Now I have hesitation on accelerating from a stop, but ONLY AFTER THE ENGINE IS FULLY WARMED UP.

 

I reset my computer the other day on my G myself. Took less than a minute and the car is smoother and more responsive.

Would recommend perform this yourself, for free. I am happy I did. Even if this doesn't help it's good to know this anyways:

The Easy Method:

After experimenting with different timing, and reading posts by other members, I've come up with a condensed method of doing this reset. This method works EVERY time, even w/o a stopwatch. I've used this method successfully a dozen times, or so, now w/o a watch. After a few times, you won't need a watch or instructions. You'll get so darn good at it, you'll find yourself doing it while waiting at a traffic light.

Timing is not as critical with this method...no stop watch needed. Just count in your head...one-one thousand, two-one thousand, etc, or use stop watch. The most critical step is step #3....wait 10 sec, instead of 7.

1. Ignition "ON", count to 3.
2. Depress/Release pedal 5 times...hard and fast.
3. Count to 10 (not 7!) and fully depress pedal
4. Count to 12 (SES should be blinking), release pedal
5. Count to 10, depress pedal
6. Count to 10, release pedal.
7. Turn off ignition, then start engine. Done!

Accelerator Pedal Release Position Learning

Operation Procedure

1. Make sure that the accelerator pedal is fully released.
2. Turn ignition switch “ON” and wait at least 2 seconds.
3. Turn ignition switch “OFF” wait at least 10 seconds.
4. Turn ignition switch “ON” and wait at least 2 seconds.
5. Turn ignition switch “OFF” wait at least 10 seconds.

 

Hey Dirty K.

So would this procedure be pretty much the same thing as if you disconnected your battery for a half hour?

The reason I ask is because I did just that, disconnected my battery to change my headlight bulb, and now I have the hesitation issue.

Others are saying to drive it for a couple days and it will return to normal, but would doing this reset procedure help, or is that essentially what happened when I disconnected the battery and now I just need to be patient with the ECU relearn?

_Michael

 

Yes and yes

 

Thanks for the quick reply VQSmile.

I assumed as much.

I was particularly curious about this because I am annoyed that by removing the battery terminal (or the battery altogether for that matter) that this would be the result.

So I wonder, this hesitation issue and ECU relearn will happen EVERYTIME I disconnect the battery for any reason?

Any idea how long the relearn takes?

_Michael

 

In general, yes; anytime you disconnect the battery, you will reset the ecu. The only caveat being that there is some latency to the charge retention within the car's electrical system (and hence the ecu), so theoretically if you only disconnected it for a very brief period of time, you might be able to avoid a reset, but with anything more, you're going to get a reset. This is why, when trying to ensure a complete system reset, you may come across instructions to pump the brakes (to activate the lights and use up residual charge) and/or leave the battery cable disconnected for a longer period of time.

The time to relearn is variable, depending on numerous factors( #starts, #miles, #shifts,etc.), so I can't say. There is probably some algorithm for how many cycles of all the parameters it needs to see before it makes an incremental adjustment.