Question to all:
Have any of you done the induction service or were recommended to so by the dealer?

Anyone i talk to about this seems to point to the A/F ratio.

The dealer was unable to verify the shudder, and i can safely say that i've been unable to reproduce it since i've ran a bottle of Techron fuel injector cleaner. I'm burning through a 2nd bottle right now.

Also, maybe the car doesn't like certain brands of gas. I've been religiously using Shell V-Power, but it actually seems to run noticeably smoother with Sunoco 93.

I'd hate to throw another variable in this issue, but i think it's cheap enough to test!

 

Here is a general description of what the problem is:
Under normal engine/transmission operation there is smooth response between the throttle and the response of the car. Depressing the accelerator increases engine rpm and vehicle speed, holding the accelerator steady maintains constant speed, letting off the accelerator allows the vehicle to gradually decelerate.
During the Shudder/Judder/Stutter issue…depressing the accelerator causes slipping/bucking (engine increases rpm but vehicle doesn’t not accelerate smoothly), holding the accelerator steady allows the vehicle to jerk (same engine rpm but rapidly varying vehicle speed), letting off the accelerator can cause sudden jerk or abrupt downshift. The Shudder/Judder is a pulsing change in vehicle speed and shaking of the vehicle at about 2-5Hz (pulses per second). It is noticeable to driver and passenger.

Here is a description of the conditions when the problem DOES occur:
Most likely: Transmission in D (fifth gear) and traveling between 35mph and 45mph (around 60kph) on uneven road surface or uphill.
Still likely: Transmission in DS (fifth gear) and traveling between 35mph and 45mph (around 60kph).
Still likely: Transmission in D (fifth gear) and traveling between 35mph and 45mph (around 60kph).
Possible: Transmission in DS (fourth gear) and traveling between 35mph and 45mph (around 60kph).
Possible: Transmission in D and braking, vehicle reaches around 25mph (around 40kph) (Same shudder feeling, but only in the transient state).

When the Shudder/Judder is present doing the following DOES NOT stop the issue:
Gradually or Rapidly increasing accelerator position (and still staying in the 35-45mph range.
Shifting from D to DS
Downshifting D mode to DS4 (shudder improves/changes, but still is not normal)
Braking and applying accelerator to hold speed range (may or may not stop the issue)
Changing AC (on/off)

When the Shudder/Judder is present doing the following STOPS the issue:
Shifting into neutral without breaking totally stops the issue (it is not suspension/tire related)
Shifting into DS3 increases rpm and changes vehicle speed stopping the issue.
Traveling on a downhill slope and reducing accelerator to hold constant speed in the range (around 60kph).
[My car does not shudder under hard acceleration from a dead stop…it passes right through 35-45mph without a glitch]

Worst case:
Shudder/Judder is occurring and full accelerator is applied…Vehicle suffers one or two hard jerks (like a clutch slipping…but this is an AT), and then vehicle accelerates smoothly. This same action when vehicle is not experiencing the issue simply produces a smooth and rapid acceleration.
I have also experienced a hard jerk when the car is downshifting into 2nd during braking. This is rare, but is transmission related and could be a result/symptom of the shudder issue.

Here is what I speculate:
Nissan/Infiniti/(Renault) must know what is going on here.
If they do know, then I assume the following: 1- They do not know which vehicles are affected (if it was a specific population then they could campaign those cars) 2- They do not feel it is a safety/recall issue (they are likely thinking “fix as they fail”) 3-The fix is not cheap or easy (or they might have more TSBs to improve customer satisfaction) 4- There may be multiple systems involved or progressive damage that make the resolution difficult.

It seems that the valve bodies are related to the issue. There are two separate TSBs that require the replacement of valve bodies, so there is some issue there. Unfortunately those who have had this done reported that the issue improves but returns or is not completely eliminated. It may also be related to accelerator/ECU programming, as the updated ECS program also seems to help but not fix the issue. Others have reported improvement from adjustment/replacement of the throttle bodies, but some of the symptoms are clearly transmission related and not engine specific.
There is speculation that there may be an issue with the torque converter (as this would explain many of the symptoms) there is also possibility that there is an issue with transmission/motor mounts or some structural resonance. The fact that the issue is vehicle speed related is a clear clue to the nature of the problem. There are several factors induced by the combination of vehicle/engine/transmission speed. Some of my thought on that: 1- The ram air to the engine could cause misreading of the MAS or turbulence at the TB and make the engine power “flutter”…perhaps this sets off a separate issue in the transmission (if installing a POP system makes this condition change, then the airflow might be a factor). 2-The drive system could have a resonance that feeds back through the transmission (this is less likely because it is happening on RWD and AWD versions of the Gs). 3- The motor/transmission mounts might have a resonance that sets off at this speed and causes the valves to malfunction (maybe the good valve sets are not so sensitive). 4- the most likely is the combination of transmission gear and engine HP (low speed, high gear, low HP = unstable condition).

I also have a 2007 Honda Odyssey van…Honda issued a TSB for reprogramming to solve a Judder issue. My van has/had the judder and it is very similar to the Infinity issue, but not as severe (jerking/slipping is not as noticeable). I bought the van new and the problem presented and then started getting worst with miles/age. I had the reprogramming preformed, and it made it “better”, but it started getting worse again. You can search this issue and there are two clear factors here: 1) programming 2) torque converter. There are stories that dealerships replaced torque converters (without reprogramming) and the problem returns in a year or so. There are stories (like mine) that the reprogramming was done but no new torque convert installed, and the problem is not fixed. The answer is pretty clear…the programming allowed/caused damage to the torque converter and the fix is to reprogram the computer and replace the torque converter. (Honda Info:” 09-053 July 14, 2009 Applies To: See VEHICLES AFFECTED - Product Update: Lock-Up Clutch Judders Between 20-45 MPH - BACKGROUND:A judder from the torque converter lock-up clutch may be felt while driving between 20-45 mph. To minimize the judder, a PCM A/T software update is available. If the judder returns sometime in the future, after the PCM A/T software is updated, the torque converter would need to be replaced.”)

At the moment, my conclusion (without any more data/facts) is that the programming on the Gs has combined with torque converter and valve issues to trash the valves and torque converter If the ECU is telling the valves to operate (open/close) at an unreasonable rate then this is bad for the valves and could damage them. If the valves are bad, they could be telling the torque converter to lock-up/disengage to often or at the wrong times. The T/C would be damaged by this behavior and would also cause abnormal loading on the transmission and engine/transmission mounts.
The end result of this domino effect could be a vehicle that has valve, torque converter, transmission, and mount damage and requires replacement of all items to return to normal driving. It may be that the damage is cumulative such that the worse to valves are the more damage the torque converter sustains. It can also be that replacing the valves and leaving a damaged torque converter makes more work for the valves and shortens the life of the new set.
If the root cause was actually the programming, then it makes sense in the eyes of the manufacturer to start with that repair. The root problem may indeed be a simple programming error, but they don’t want to advertise that it is best to get a reprogram and a new transmission + torque converter (they can afford it). Unfortunately, some of the damage will likely lead to failures at a later time and may cost the drive thousands in repair out of warranty period.

My fear is clearly that the transmission will die when out of warranty, and this issue that could have been fixed will be on my dime. I do not want to get anything I don’t need or deserve from Nissan, but this really isn’t right that there is a serious and progressive problem with my car and they are playing dumb.

If anyone else have more information or finds a root cause (solution), please feel free to use my info here and expand into a better summary and recommendation.

KMC

 

KMC: I had a very similar JUDDER with my Nisan 2005 Altima 3.5 V-6 SL. it did not start off that way but at about 20k miles. That JUDDER...sudden jolts while in stop and go traffic at 35-20 mph. Nissan changed the Valve Body. it was better from the get go, but deteriorated rapidly and the JUDDER was worse. I never went back to push the issue. No time, leased vehicle, and the lease was coming up soon. A very good local mechanic at the time in Long Island, looked at the car for me. He said it is not really a valve body issue but a Torque Converter issue. That's what needs to be replaced.

With my former 07 G35X, I did experience a hard shift into 3rd gear after abnout 10k miles. Dealer replaced the valve body w/o question or forth-thought. The hard shift seemed to be eliminated, it was much better anyway. The hard shift was more experienced while cold and if I used the Manual mode more than normal D mode. Likewise as you describe, I did feel sudden hard downshifts into 2nd gear - rare - mostly on coming to slow stop on a downward sloping road... After complaining about the the returning hard shift maybe 6 months later, the Dealer tost drove without me, called me to say that they are ordering a new TRANNY, received approval from Infiniti in a few days, and installed in a few hours on the same day i brought it in... tremendous service from Pepe Infiniti where leased the car. Problems were GONE with the new Tranny. All on warranty of course. Didn't cost me a Dime!! Now, I have new 2010 G37X with the 7 spd Tranny (Auto) - crappy performance compared to the 07 5AT....Sorry i didn't buy my 07 - only ha 25k miles on the clock after 36 months: like i tell my sons - young adults - "Newer is not always better".....Should have practiced What I preach !!

 

Almatti: Thanks for the info. I am really building confidence that this issue requires a new TC to really be right. It does seem that the valves are to blame for the hard downshift. It is likely that a reprogram, valve set and TC will fix all the problems, but at that point it makes sense to replace the whole tranny. There could be obvious damage to other components if the valves and TC are not working correctly.
Glad to hear you have a top notch Infiniti dealer.
As far as the new G35 goes...I had a loaner the other day, and popped it into manual shift...yikes, I forgot those were 7 speed, and I have to say it is not as fun as the AT5 in manual shift. I do like other improvements.

 

i have an 07 g35x and i have all these problems, i had the cruise flash did nothing... i had the trans flash it only dumbed the car down, they gave me an ecu update and all that did was take care of the throttle sensitivity. i pulled a mechanic aside at infiniti and i was told off the books there is a real big problem with our transmissions and infiniti is quietly holding there breath about it. im raising holy hell with corporate and getting my lawyer involved. this must be rectified. i spent 30,000$ on my car im not about to feel like im driving a hyundai.

 

I have filed two complaints with the corporate office. I will be contacting the better business bureau in NH where my dealership is per the advice of my attorney as well this week. Its obvious these crooks know what is goin on after thousands of complaints only to tell their 'customers' everything is within normal specs . No brand loyal/repeat customer here.

 

Thank you guys for trying to get infiniti's attention.

My shudder has come back full force again. Seems to come & go.
I may get the extended warranty as to not get the shaft when they do finally release a fix for this!

 

i've got nothing new..i've been so busy i havent even been able to file a claim with the better business bureau yet. anyone have anything new?

 

I can report that my car occasionally shudders once again, not so often as before my ECU reflash, but occasional enough to concern me.
I don't know where to go from here, treacherous says a flush might help it out, but I don't know anymore guys, only have 40,000 kms and I'm getting tired of fighting with the dealer (three visits for this already).

 

Same here, the shudder seems to come & go without consistency. I though i had it down to science, but apparently not.

Johnyzee, i've had the flash, the flush, MAF/injector cleaning, and almost everything else you could think of. The shudder's still there, though maybe not as bad as it used to be, so doing all of those things can't hurt.

 

Anyone do the Transgo valve body upgrade and still having the problem?

 

Some1 should setup a poll 4 this so we can see the %/# of cars this has affected.

 

this should be considered a lemon if they can't fix this issue right? They obviously know what is wrong but they just wont open their fat *** wallets to fix this.

 

Funny, I was considering doing this eventually. Is this available for our cars? (2nd gen g sedan)



to heynow: thanks for the info, seems there really isn't a cure yet, even after all your attempts. I'm unfortunately really just getting used to living with this, but the transgo valve body upgrade is sparking my interest. i'm wondering if this will cure the issue.

 

that valve update looks like a pretty promising investment just for making my shifts a little crisper- can anyone thats added this to their 07-08 with this shuddering/shaking issue chime in? My issue on my car is that when i am just cruising and then take my foot off the gas to coast ill be fine until i just lightly apply throttle and experience this death shudder. if this helps i'll use it as an excuse to but it haha