Hopefully someone will find the cause and that wouldn't be a bad idea to leave it at Carriage over night...I'm sure they will fix it if they can replicate the problem...

Yeah, I loved the XO2, but my girlfriend thought it was too loud inside the car:) I wanted the Borla really anyways and got a good deal on it used....We'll have to get together again soon...

Had a customer in today w/ the same complaint, no codes stored, Kept the car for 2 days... when veh is at operating temperature nothing happened... logged about 2 hours in the car w/o noticing anything different...

wow im surprised to see this many owners with this problem, i thought the clutch issues would be the the only problem we encounter but unfortunately its not. as for me i have yet to notice this problem with mine, yet again i only have 6300 miles on my 07 as to the ones with problems have about 9000 miles and above.

Interestingly this seems to have started during the end of October, just about the time winter gas starts to arrive at gas stations. I would bet there is a connection between everyone's rough idle and the poor quality of winter gas.

Mine started well before October, it started in July. It's not what I would call rough idle, it happens at a very specific time during the warm up cycle. Not completely cold, but not up to normal operating temperatures either.

Same here, no codes stored which basically means it's not affecting emissions since that's what the codes are basically geared around.

I don't think you're going to find this problem at normal operating temps. To find it, a tech is going to have to drive it after sitting overnight, and pay very close attention to throttle input, especially during gear changes and/or being completely off the throttle (coasting) then getting back on it.

If you apply anything other than light throttle (something in the 5-10% range) it probably will not be felt. Once you find it the first time you will have no problem duplicating it.

I started to experience this problem after switching from Mobil 5w30 to Mobil 0w40 Synthetic and filling up with 76 Gas so it has to be one or the other... I'm gonna fill up with Shell after this tank, and if it keeps acting up I'm going to drain the 0w40 and replace it with 10w30.

Can someone give me a theoretical explanation of how the type/brand of oil could affect/cause this issue? I just don't see it.

Fuel I could see possibly, although I've had the issue with different brands (BP,Shell,Chevron) all 93 octane.

Yup i have it too...07 with this problem. it "hiccups"after you let off the gas completly then u just barely tap it.

happens after the car has been running for 4-5 minutes. the car will start to buck pretty bad under light throttle from 1700-2200 RPM's. I'd really love a solution because it's getting pretty annoying when i'm just trying to accelerate slow or idle forward and my car starts kicking..... I almost re-ended someone because of this problem.

Yeah that sounds right based on what I've been experiencing. Mine isn't as bad as it used to be however (it used to be every time I started it up if it had sat still for long at all). Now it's... intermittent, but it still happens too much.

If I could be SURE it was going to happen "next time", I'd have it at the dealer now.

Does anyone think we could get some actual interest from Nissan if we all tell them we're having the problem. Isn't there a guy in this thread that works at a dealership? Give us some pointers here...I just want to get it addressed.

Well, I also own a 2007 and have not had the issue yet... I have been trying to be able to put a finger on it, to look for a problem, but the problem I'm having is that this condition is so rare and so hard to duplicate that nissan won't see it as an issue. There are no codes present (check engine light) and if a dealership cannot dulicate the concern, nissan won't research anything about it. You can always call Nissan Consumer Affairs, but they will ask you to bring a car to a dealership b4 calling them... Phone number is on the owners manual...

I'm going to take a stab at this. I do not own a 350 but I plan to get an 07+ 350 base so I am following this closely.

From my experience with the symptoms you guys are having, the only time I had this sputtering and power loss was on the track when I use to get fuel lock due to my baffle being to large.

Now I'm not saying it has anything to do with the baffle but I think this is a fuel delivery problem more so than type of oil/fuel is being used. And since people report that they are using quality oils with quality fuel and that plugs are fine then I doubt those are the problems.

This is just a guess, but I have heard that some OEM fuel lines in some cars (not necessarily Nissans) are low quality. Perhaps the new 350's fuel lines are low quality and too flexible.

At start up the lines are cold and perhaps the material shrinks and causes pinching in some areas. So the fuel hiccups pass the pinch but ultimately does get to the engine. After driving it a bit the lines open up and flow freely. If you stay at a certain RPM it hesitates/sputters maybe because at that RPM not enough pressure is going through the lines to open them up.

Just a guess. Another thing is, when my buddy built some race engines, he ordered AEM fuel rail. The AEM fuel rail fuel line inlet was not even drilled all the way through!! Fuel was barely getting into the fuel rails. So manufactures do make mistakes. Hell maybe the HR fuel rails are faulty?

Hope this gets resolved though.

^^^ good possibility

whatever it is, its a physical, mechanical issue because for those of us with aftermarket exhausts, we can hear the differance. The sound coming from the exhaust will sound normal then all of a sudden, the exhaust sounds more throatier while the issue happens, then goes away back to the normal sound..

damn nissan..

Yeah keep me posted, my Z sounds a bit rough for a engine with 2500 miles on it. I mean I hammer that ****ing thing but hey I did that with all my cars and my friend has done it with his Z and G. Yeah lets hope its something under warranty .

Adding on to my theory, it could possibly be a bad FPR as well? The argument of the ECU picking it up is semi-valid. If the FPR was built low quality the ECU is meant to read it that way so it won't through a CEL even if it was under-performing.

GodSendsDeath you drive an 08 and you think you may have this problem? That is not good since I was banking on the 08's to have fixed both the clutch and this problem.

My 2006 has just started doing this, one day it felt like the engine shut off at full throttle in first gear. It always does it between 2500-3000rpms at about the same throttle position. I am going to log it with my osiris and see what its doing but i suspect its the TPS or something related to it.

I've always kind of thought the TPS also.. let us know your results

If it is something to do with the fuel delivery, AAM's new fuel system and rail might be a good solution...

I have yet to see somebody w/ the issue where there is anything other then momentary and very hard to duplicate. when all the sensors are checked everything falls under the parameters.... this is going to be hard to find, really not looking forward to trying to solve this...

Mine has stopped doing it since I switched from Chevron gas to Shell. Go figure.

At one time, mine did it EVERY time you started it up after sitting for a while. You could probably have seen it happening without being in the car at all. Now, it's not nearly as often..and doesn't seem to be as "bad" when it does. I could kick myself for not getting it down there when it was really bad.

That being said, it's still not correct during that time.. it's flat and not running as smooth as the engine is capable of. The only real changes between then and now are colder temperatures, and more miles on the car.

i shall attempt this but not too hopeful.

also just a quick note, I'm not sure how much nissan is going to support us on this problem. I spoke with a very reputable dealership on this forum and even they were telling me that they might have a hardtime covering this fix under warrenty simply from the fact they cant figure out what it is and they can't just start replacing random parts by guessing. Please note, this doesnt mean they will NOT warrenty, but here is a sum up of the conversation.

I asked if Nissan would cover a rental car while i left my Z at their dealership for a few days so the techs could drive the car multiple times throughout several days. Basic response was Nissan MIGHT cover rental, but also might not. Reason being that EVEN IF the tech acknowledges the problem(meaning he know it exists), if they cannot diagnose what the exact problem is(which at this time doesnt seem like anyone can because the ECU isn't logging anything) Nissan will not cover this as warrenty work, hence the no reimbursment for rental car. I'm sure the dealerships wont charge us for checking out the problem, however, just don't expect any favors like rental reimbursment or compensation for anything.

I was told merely that the ecu wasn't throwing a code. Okay, I'm not sure that's the same thing as saying it is not logging anything.

Additionally, I'm pretty sure if they hook in a logging computer (of some kind) that they're going to see SOMETHING going on during these times.

As far as the rental, I couldn't care less ... I have another vehicle anyway. I'll try to be the guinea pig on this one... within the next couple of weeks. I'll get the slave cylinder upgrade at the same time.

Chevron is all I use every single time. I've maybe swayed outside of chevron 2-3 times in 10k miles. Not a single issue.. I'm running aftermarket HFCs and nismo exhaust.

goodluck! keep us updated. I'd do it but my Z is my daily driver. :-(

I thought they replaced the Slave Cylinder when you had the clutch issue..

They did, they replaced everything. I would assume however (being that mine was one of the first to actually get "fixed" that the slave cylinder is the same one that came out of it originally. I doubt seriously that I got the updated one.

One of my customers (33k) started having this issue, but again not as noticeable... I personally printed 30 min worth of data and compared to specs, the only thing I saw was that at some points the A/F mixture passed 110% by 1 or 2 percent, but other than that it was fine...the HR reads diferent on B1 and B2 and the diference was a litle greater. When parts were tested independly, they checked ok, therefore there was nothing to replace... That's why I say, this is going be tough o crack, and It won't happen untill someone throws a CEL...

True, I may need to see about mine as well...I also have to take my car back up there for a clicking noise when starting from a dead stop..Almost sounds like a bad axle...I'm starting to wish I had kept my s2000 :(

can you explain the "1 or 2 % more than 110%"? I'm used to seeing ratios, so I'm not sure what you said means.

i'm sorrry I meant A/F Alpha

Anyone check injectors? The old Z32s had injectors that would clog out of nowhere and produce the symptoms like you guys are mentioning; just like a fuel starved engine.

I haven't, but that's a good idea. That's exactly what it feels like. I'm just surprised that it seems to be ALL cylinders.

just to add to the observations i was playing around with my car today. The issue will only happen under load. When my car started to act up and i stopped immediately and started reving my motor. The motor revs just fine. Smoothe, no issues. Then when i put in gear and try to go forward, once again the car started to jerk and shake...*sigh*

that's a good find..... the more info the beter to find the issue

That sounds like the slave cylinder problem.

i thought the slave cylinder problem had to deal with the clutch dropping to the floor?

i could be wrong, guess i'll go read that thread.

update, My car is going in for recall service on Monday, and a very reputible service writter otherwise known as Tim@performance said that while my car is there, they are going to investigate this issue. I've already linked him to this thread so lets hope they come up with something!

Keep us updated.. I gave a crack at solving this w/o luck... we really have to pass the info on to get this solved...

I think that after market intakes might have somthing to do with it? I have the completly sealed stillen's and havent had any of these type of issues.

nuh... my cust had the stockies.... so I dunno, I have had a couple of cars, and then problem is, Nissan does not pay to try to find the problem, and it's tough to duplicate, b/c only happens during warm up, and the computer does not have parameters set for a cold start... all the parameters I have is for a fully warmed up (not just coolant, but oil as well) engine

Yep, stock intakes here as well.

the problem with this i see is the problem would either be constant, or it would occur upon startup, and then go away as the ecu adjust fuel/air ratios etc etc.

The car drives perfectly fine for a few minutes, then the problem starts, then goes away.

So Tim from Performance called me and he's been really great about trying to assist me. Unfortunately when him and the tech took out my car this morning they couldn't duplicate the problem. I was literally shocked because i've never had the problem NOT happen on a cold morning start. He said that they are having some kind of regional master tech stop by to give it a shot and if he cant duplicate it, I'm going to the dealership first thing tomorrow morning to see if i can duplicate it myself with the tech in the car. *sigh*

update: teh master tech drove it and could not duplicate the problem either.. I wonder if this problem truely is associated with the clutch recall...(my clutch got serviced before they started testing for the sputtering)

guess we'll see when i go in tomorrow..

Mine used to act up every time that my car sat for a while. I just got my recall done 2 days ago.........haven't noticed it since....I'll try today at lunch to see if i can duplicate it, but the recall might have fixed it.

Alright, I tested it at lunch and It's definately gone, I couldn't get it to act up at all. Since mine was pretty religous about doing every time the car sat for alittle while, I'd have to say the recall fixed it. Atleast in my case, goodluck to every one else having this problem and get your recall done ASAP!...feels so much better overall.

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..