---Hesitation at ~40mph--- Input Request!

[gloa2000]

I have this problem but i simply give full throttle to accelerate at that point and i like it

[302@12psi]

I've had this issue a few times as well. Althrough until now I just wrote it off as the way I drive the car and it's "learning".

I drive the car pretty easy. It hardly ever see WOT runs, usually shift's automatically under 3k rpms, hardly ever downshifts on the highway, and usually get 22-23MPG.

So my driving is lite to say the least.

My experiance has been cruising at 40-50 MPH and trying to put the pedal down to pass. It "hesitates" for a nano-second and then the "rush" feeling is on. It does not feel as if the engine has overcome a torque curve drop but rather the RPMS havent caught up to the gearing yet if that makes sense.

Again I wrote my experiance off as the ECU not really understanding what I wanted it to do with fuel/timing at that particule RPM as I normally do not drive that way.

I do not use DS or Manual mode so I can not say if it happens in them.

[cjre1]

I have this problem but i simply give full throttle to accelerate at that point and i like it

That is one way of doing it.

[abyss]

I too have noticed this hesitation. It occurs at around 40 mph with the car in 5th gear. The engine seems to be turning at about 1150 rpm. When trying to accelerate, there is a momentary hesitation before a downshift and acceleration. I believe what we are all experiencing is the unlocking of the torque convertor (Steve, cover me on this). But this car, like all automatic transmission cars now, have a locking torque convertor. The torque convertor is a fluid coupling between the engine and the transmission, allowing the transmission to change gears. But as a fluid coupling, there is some power loss, due to the convertor. In an effort to eliminate these losses, the torque convertor can be locked, thereby eliminating the loss. Now generally, the torque convertor will only lock up when the transmission is in the higher gear ratio. Once locked, the transmission can not downshift to a lower gear until the torque convertor has had time to unlock. and hence, the hesitation we are all experiencing. At 40 mph and 1100 rpm, I am not even sure how much pressure is readily available to unlock the convertor, so the transmission can downshift. This seems to be an issue of over-zealous programming of the torque convertor to increase mileage. I would think Infiniti should look at increasing the rpm range before it allows the torque convertor to lock up, such as in the area of 50 mph. I am not sure how much fuel economy advantage there is in locking up the convertor at these low speeds, as opposing to the increased time it takes to unlock the convertor and achieve a downshift and acceleration.

[cjre1]

Funny thing, because once the dealer updated my ECM (ECU) and TCM the hesitation went away. I posted on another post about all the issues I had and the fixes for them.

This does not work on all cars, I was told.

[fleiscd]

I've experience this issue on my EX. I noticed (and noted in a different thread) that when I had my EX in for service and had a loaner EX that it was much more responsive and didn't hesitate like my EX. It was a very noticable difference. I thought it might have something to do with the fuel pump but reading this thread I see that is not the case.

[cjre1]

I've experience this issue on my EX. I noticed (and noted in a different thread) that when I had my EX in for service and had a loaner EX that it was much more responsive and didn't hesitate like my EX. It was a very noticable difference. I thought it might have something to do with the fuel pump but reading this thread I see that is not the case.

Man, it can be a combination of issues, like my car had. I have a service record of 9 items fixed on my car and updated the flash. At least one of the fixes took care of my hesitation issue.

If nothing works, it sounds like a lemon, but you need to research and define a lemon in your state.

Please let us know what happens.

[RCHarris]

Last summer I reported this problem to my dealer who tried to convince me that the lag was related to the "drive by wire" system. He said the throttle pedal takes a few micro seconds to communicate to the ECU that it wants to accelerate and that the net result is that hesitation feeling like a severe case of turbo lag. Fine except that the G35 loaners didn't have this issue. The dealer also said that I should relax because this motor was the best Infiniti had to offer, with millions of them on the road in other new Infiniti models. That sounded so fishy to me at the time, but no one here was experiencing the same issues.

There are times when the car feels as if it is taking a big gulp of air before shifting gears and then when it does it will sometimes over rev all the way up to rev limiter. Very scary! Anyway, now that it is obvious that there is a reported and acknowledged issue I will return the car to the dealer for a resolution.

Upon delivery, my car had 118 miles on the odometer. I suspected at the time that it was a dealer demo car from another dealership and that the self-learning ECU was confused or mistreated by careless salesmen and test drivers. I suggested that to the dealer too. I was stonewalled on that one. Oh well...

Randy

[cjre1]

Randy,

That sounds right to me, since every driver is different the car acts different. I had three loaners and all of them are different. One even felt like it was going to stall each time it shifts, like you describe it, an air pocket. Crazy!!!

Out of all the loaners, my car does not even act like this, thanks to God.

It will take the ECM a while to learn. Sounds like you know more about your car then the dealer does.