Sluggish performance - 06 M35x

[MasterFoo]

When I said the ECU needed to be updated I wasnt clear. I assume the Transmission has a separate Control Unit/computer and that was what needed the update not the the Engine Computer/ECU.

I am still not happy with the performance of the transmission, its still not 100% in my opinion. The dealer said they changed the transmission fluid when I bought the car, but I am now doubting this. I plan to have the transmission fluid changed to see if there is any improvement.

Cheers

I'm experiencing similar issue as I stated above, I have done the transmission fluid change (on the same day as my previous post) and it has not made any difference to me.

I am going to schedule an appointment with the service department about my ECU, because as you can see below (if it's showing), my MPG is horrible also. There is something up with the engine or transmission.

[EniGmA1987]

You should ask them to do a 2 degree timing advance. The dealership should be fine with doing it. People who dont know what it really is might say dumb things about it voiding warranty (which it shouldnt), or that it could cause problems, but it wont. Then see how the "sluggish performance" is. and gas mileage

[Theo]

You should ask them to do a 2 degree timing advance. The dealership should be fine with doing it. People who dont know what it really is might say dumb things about it voiding warranty (which it shouldnt), or that it could cause problems, but it wont. Then see how the "sluggish performance" is. and gas mileage

Speaking strictly of the transmission issues, where it doesn't seem to find the correct gear at highways speeds, over rev's when passing and in some cases a delay in throttle response I dont understand how a timing advance will correct a transmission issue?

[EniGmA1987]

I am talking about the sluggish performance when going slow, not highway speeds.

And I have no idea what your talking about with not finding the right gear or over reving. The ECU learns, and the ECU controls how the car runs and shifts, so you probably just happen to be driving the car in the least optimum way for the ECU to work well.

[Theo]

I am talking about the sluggish performance when going slow, not highway speeds.

And I have no idea what your talking about with not finding the right gear or over reving. The ECU learns, and the ECU controls how the car runs and shifts, so you probably just happen to be driving the car in the least optimum way for the ECU to work well.

The thread was/is related to an apparent transmission issue.. I had issues with throttle response below 15mph where there was a second or so lag when pressing on the pedal and what felt like a transmission slip where it over- revved when trying to pass or accelerate almost like missing a gear and going into neutral with a manual transmission. The dealer flashed, what I thought is the Trany computer, with the latest firmware. The situation has improved since but it has acted up in some situations.

Its doubtful the issues discussed here have anything to do with driving in the optimum way.

[jeostang50]

Anyone get a definite fix on this? I'm having the same issue. Its almost dangerous, with trying to pass someone you pull into the next lane and the car decides not to go when you floor it.

[Lynchr]

I bought my 06 M35X from an 88 year old gentleman 3 years ago. The transmission shifts promptly on both up and down shifts. There is no hesitation at all and it is very responsive.

He provided all service records from new. While reviewing them I saw were the dealer had preformed the trans service, and then 6 weeks later an Independent shop "sold" him a transmission service again. On the independent's repair order it just stated xx quarts of transmission fluid.

I took the car to my Infiniti dealer to have the fluid changed again and emphasized that I expected that Nissan Matic J fluid be used. I was assured it would be.

While paying my bill I glanced at the RO and saw xx quarts of bulk transmission charged out. I confronted the service manager about not using Nissan fluid and his reply was "we know what we are doing".

I told him I was from Nissan Corporate, Service Operations, and he didn't know what he was talking about, and he should check the service manual for fluid requirements. He agreed to replace the fluid again with Matic J. Interestingly, not long after this, the dealership had a new owner.

The reason I'm explaining all this is so that DIY'ers understand how important the fluid is. The following is taken from the M service manual (I think it is also stated in the owner's manual):

"CAUTION:
Use only genuine NISSAN Matic J ATF. Do not mix with other ATF.
Using ATF other than genuine NISSAN Matic J ATF will cause deterioration in drivability and automatic transmission durability, and may damage the automatic transmission, which is not covered by the warranty."

If I recall correctly, Matic J has been replaced with Matic S.

Not knowing the OP's car history this could be a factor. All the symptoms mentioned sound like the clutches are slipping. Also, if water ever got in the trans (such as in a flood, or driving through high water) it will also take out the clutches if not immediately flushed out.

Sorry for the novel.