It looks like part of the major issue with the lag, harsh downshifts, etc MIGHT be because of what RPMs the engine happens to be at at any given point.

Most likely the 3.7L will have different RPMs for a given speed than the 2.5L, so the 2.5 could be *masking* the issue, but the issue is still there.

The same masking can be seen when you have the 3.7 in manual mode, and a little in DS mode........the RPMs stay slightly higher because of the shift mode, so you tend to see less lag and shift confusion because the whole setup is staying above a certain point (the magic RPM seems to be around 1600 or so)

 

^Meaning the final drive ratio is different in both cars? Meaning the RPMs should be different at, say, 60MPH or 70MPH? I doubt it because they are identical as far as my observation is concerned; unless it is so minute that you need a very skilled eye.

 

I unfortunately had the reflash done to my 2010 G37 when I had my car serviced. I did not realize this was done until I picked up my car and got on the highway. I generally always drive in DS mode. When I started driving I felt hesitation as I floored it, I felt that the gears were not holding as I took my foot the accelerator, and I felt no engine braking. I am so disappointed with how the car drives now. I neither feel nor see any difference between the DS mode and D mode. I took the car back to the dealership and they tell me that there is nothing they can do. This is absurd. I never asked for the reflash and I now have to drive a car in which I am truly not happy with.

 

They are the same...
that's correct. So we're back to no explanation for the difference. Strange.

 

Technically they can replace the units that were flashed with units that don't have the update yet.....but that might be a stretch. I'm surprised the dealer flashed it on their own without any tranny related complaint

 

I just want them to "flash" mine with the same program they use in the G25....how hard could that be!

 

Why would they be the same? A 3.7L engine and a 2.5L engine are going to produce the same HP at the same RPMs and gear?

 

The final drive and gearing is what determines your RPMs at any given speed. HP and torque and powerband determine how fast/smooth you get there.

The final drive is the same for the G25 and the G37, and the 7AT has one gear set in it for both vehicles as well AFAIK.

Now, the 3.7L having more power and a different powerband could technically explain the harsh/laggy shifting compared to the 2.5L, but thats a stretch, unless Nissan is trying to chince out and have the same exact program on the TCM for both vehicles and is searching for a happy medium that works. Perhaps the 2.5L has more low end torque (especially around the magic 1500 RPM point that seems to be laggy on the 3.7L) so the TCM isnt trying to figure out what to do at that point like it is on the 3.7L.

Its interesting that somewhere in this thread someone mentioned a tech directly from Japan sat with him *in his G25* while he recreated the lag issue. They took lots of notes, but I havent seen any update from the poster to see if anything came of it (Im also not sure if they sat with him before or after the most current TSB flash)

 

Great Posts Chris11..... I concur with the other member who had his G37 reflashed w/o asking... There is avery little difference in DS and D modes, seems about the same to me both before and after the reflash, but IT IS DEFINETELY NOT THE DS mode of the 07 G35X I had, not even close. Damn this 7 AT, it has been produced to get more mileage and now More Misery in this fantastic automobile.

We need to keep this up. All of the members who either read this thread and agree with the problems posted here, whether or not you psot comments here, should email, call or mail Infiniti USA and continue to complain about this driveability issue. It has Ruined the car, and you will notice it if you have had the 07 or 08 G35, FOR SURE!!!

I for one, will keep bring it back to my Dealer - Pepe Infiniti in White Plains, NY, they won't be able to fix it, but my intention is to get a Regional Infiniti Manager to drive it, log it as continual complaint and let the engineers be advised. They need to hear this from EVERRYBODY....2010, 2009s, and now 2011s... Thansk for listeneing to my gripes. Man, If I had "felt" this in test drive in June, never would have taken this car.

 

i agree, the M35's tranny feels way better. i guess if i want smooth and fast tranny, i just drive the Audi.

 

Yup. That sums it up. Instead of a kamikaze double downshift, it just drops a gear and pulls. My wife was always like WTF! on the way to the gym on an uphill stretch after turning a corner. I use to have to baby the car to avoid the crash double downshift. The car is now a lot more pleasant to drive. It may be a 1/10 sec slower to 80mph, but who cares? It's an infiniti, not a race car.

 

It has been a while since I updated my experience here.

I expected to reset the ECU every few weeks to get the "light" feel. To my surprise, I don't have to do that yet. My G still feel "light" and the lag is minimum (read as acceptable). Either the car has adapted my driving or I have adapted the way the car drive. Either case, I'm happy with the re-flash so far.

I'll post another update in a few weeks.

 

Just had our first service today at Riverside Infiniti and I inquired about the trans reflash, then had it done. The service adviser was well aware of the "40 mph lag" due to other complaints. Trans is now reflashed and the ECM (ECU?) reset.

So I couldn't hold back and slammed the pedal down when leaving the dealership, backed off at about 40-45, then hit it again--near instant acceleration! I can't say for sure yet if there's an improvement at the 40 mph sour spot, maybe I missed it on that first attempt. Based on other reports, it will likely return? A little slow down and quick pick up here and there on the Interstate on the way home and all seemed well, but again, more driving needed and time for the car to relearn.

I did, however, instantly notice the minimized downshift and I like it. About the last mile through our residential neighborhood is on a light downhill run before reaching our home. The '03 G used to coast and keep it at 25-30 mph all the way with your foot off the accelerator pedal. The '10 would require light acceleration almost all the way to keep it at that speed range. Now it's no gas and perfect coasting at 25-30, just like the '03.

 

That's cuz the throttle is not as sensitive anymore

I bet it will be the same kamikaze downshift if the gas pedal is pressed enough.

 

After a few weeks now after the reprogram... smooth sailing...

1) no significant harsh shifts .. 80% is a number I have in my head: 80% of the harsh downshifts are gone or at least no longer felt

2) knock on wood -- no more engine dragging/braking/rubber band -- 80% better, still there.. but much better.

3) Have not yet had another of those engine rev limiting "limp mode" thing... but time will only tell.

4) acceleration is still very brisk, shifting under moderate to heavy throttle is very quick and accurate

Just my $0.02 after a few weeks... will continue to post.