guess i have bad luck. I went to the dealer to try to duplicate and it didnt happen. So i thought everything was great since their techs couldn't duplicate either. To my look, once i get home and go out again, the problem came right bcak. :-(

sigh..

 

does any type of smoke come out after a cold start before it does this?

 

just the typical light white smoke from the car warming up when its cold outside, but nothing unusual or unusual smells.

i'm going to try and reinstall my intakes this weekend see if that has anything to do with it. I'm so desperate to try anything because this is truely growing tiresome. If i can't get this resolved before my warrenty is up i think i'm just ganna trade my car for something else.(not hating Z's in general, just the one i have for being stupid)

 

that really sucks man........the one thing I don't have is intakes....but I don't think that should make a difference. I did still notice it once yesterday, so I'm truly not free from the problem. It just doesn't happen all the time, like it did before.

 

^^ I believe this is the problem guys.

I took my car to the dealer this morning because my car FINALLY threw a CEL. They have been working with me on this problem and have been skeptical until now. They are almost positive this is the problem. Basically what they were telling is that the car is SUPPOSE to run between 90-110% MAX A/F ratio. outside of this area the ECU will try to readjust but can only do so much. My personal car has been having this "sputtering" issue for quite some time and it's grone very irritating because of how violent the car can jerk sometimes. When they pulled my log, my car was spiking between 120-135% At this range, the ECU can no longer make adjustments to compensate. The reason why this issue happens consistantly at around the 5-7 minute driving mark, is because from what the dealer was explaining to me is that durring the warm up period, the A/F sensor basically stays off until the car is at normal/ideal operating temperature. Not necessarily when your temp gauge reads halfway between hot and cold. Once the car reads at the right temperature, the sensor activates and then starts to play around with the A/F ratio to make for the best driving conditions. Because when it activates and the car is running so lean(past the 110% A/F) the car basically goes into freak out mode and try's to correct the ratio which is why the car starts to act spiratic for only a few seconds. Once the ECU realizes it can no longer compensate i guess it basically just gives up and lets the car run lean. All this was explained to me by Performance Nissan which is a pretty reputable dealership in my area and on this forum so i think this is some solid information to go by.

Now the cause of why MY car is running lean, they are guessing that my fujita intakes are actually sucking in TOO MUCH air. Too me, i dont think they are BS'ing me trying to blame it on a mod, because when looking at the overall picture it actually makes some sense.

the only thing that stumps me is that noone else with fujita intakes is having this problem? So i'm going back to stock next week and i'm crossing my fingers this problem is done with.

 

Finally some good information. As far as the intakes... I'm stock intakes so that isn't the only issue. I AM running HKS dual exhaust, but if that was the issue I would think it would have happened from when I first installed it (5500 miles) as opposed to waiting till the 12500 mile mark.

The explanation makes sense however, perhaps it's the A/F sensor that's giving some bogus readings?

 

that could be a good posibility as well since noone else with my intakes is having this problem ? :-(

 

I have intakes and exhaust and never had the problem...I noticed on another forum that a guy put one of his MAF sensors in backwards when installing his intakes and he was having issues with CEL and rough idle, but I don't know if that could be the problem...

 

I wonder exactly how many people are having this problem

 

^^^ there have been several threads relating to a at least "similar" issue. Some of these involve years earlier than '07 models.

 

Still no issues since I have been using Shell gas from Chevron. Amazing.

 

Chevron is the only gas I run with no problems as well....Strange!

 

I might very well buy into the gas thing, except that I also run Chevron, and have the issue.

 

i tried switching over to shell since you posted that. I've ran about 5 tanks through it with no change.

 

I'm the OP here, and been having the same trouble for months now. I've figured out how to avoid it happening to me which involves sitting in my driveway every morning for 10 minutes.

In addition to that I've had an exhaust since day one, my car was never stock new. I had intakes for a bit which caused me some issues and removed them in less than a week.

So to recap I use only Shell or Chevron, I have stock intakes, a custom dual exhaust with x-pipe, and a couple months back I got FI HFC (Metal).

I will attest I do have an exhaust leak, which I'm hoping to get fixed on Friday.

Apparently no one has really pin anything down as the cause. Finally my Vin # starts with 1BZ which excludes me from the recall for the slave cylinder which has never given me problems.

 

Im not sure who originally proposed that it could be due to the slave cylinder but this sounds completely unrelated. I have had the slave issue and I never experienced any of those symptoms related to the sputtering.

 

So, this wednesday i'm going into the dealer to have my intakes anda exhaust put back to stock. This means my car will be entirely stock except for nismo short shifter.

If the problem doesn't go away, i'm seriously considering a lemon law attorny. What do you guys feel the chances of this will be? I seriously don't have the kind of mentality to just go out and try to sue people for money as i feel very passionately against people that are like that here in Orange County Ca, but i feel this is could be a legitimate case. input please. Or recomendations.

 

When you say sputtering does it do it when you get on the gas kind of hard at low rpms? Mine started doing that after I installed HFCs.. but if i drive normally i don't feel it. Only when I get on it at low rpms.. kinda sputters, then gets going.

 

no it's not that one. When i had HFC's i know exactly what your talking about and this is different.

This occurs only after cold starts at a very predictable 5-7 minutes of driving between the 1500-2300RPM range and will only last for a few seconds. Occurs regardless of how hard you press the gas.

 

That sucks. Hope you get it resolved. But do you know the cause of why after installing HFCs I get that too? A/f sensor going crazy?