As the title states, my 2013 F sport(46K in miles) seems to have interment kick down issues. The Rx refuses at times to drop down to an appropriate gear to match the speed of travel. Lexus seemed to have mapped the transmission to get the highest gear quickly (fuel economy) and sometimes stay in that higher gear when the RPM does not warrant it.

Yesterday, I had two instances where the throttle lag is starting to be more and more disconcerting.

First, upon transition from the middle lane to the fast lane, I gave myself ample space between cars to transition lanes. I proceeded to lean into the throttle and it delayed. A complete dead spot. It seemed like an eternity for the kickdown to take place. Now, if a car or truck were barreling down on me, this would have been downright dangerous.

Second, I made a right turn after exiting the highway, which leads to a fairly steep incline. I depressed the throttle, and Rx felt like it was struggling like an out of shape individual with a slight groan to note. I proceeded to lean further into the throttle, almost full throttle to floor and absolutely no kick down at all. I understand in both situations that I could tap the left paddle shifter to activate the brief manual mode to drop a gear or two, but it’s really troubling that I would need to do this more times than often, especially when I’m not driving overly spirited.

I know the throttle lag topic has probably been beating to death here, but I’m just trying to gain insight if it’s the throttle lag or something else going on. The dealers tend to have the same response: “Can’t replicate the issue. Vehicle operating within spec.”

The vehicle felt more spirited when it was first purchased in June. Could it be the ECU has adapted to the relaxed driving style?

My wife and I like this vehicle, but the throttle is downright vexing!!!! Thoughts?????

 

It is the nature of the early releases of the 8 speed automatic transmission which was not quite ready for prime time when Lexus started using it. Google search Toyota 8 speed transmission complaints

Also sometimes engine problems are reflected in rough transmission shifting or behavior. Try a bottle of Techron Complete Fuel System Cleaner in your gas.

There is even a lawsuit over them, although it covers 2017 and newer Highlanders. https://www.carcomplaints.com/news/2...-lawsuit.shtml

More discussion here. You may want to get the transmission fluid changed. If your dealer won't do it, call around to other Lexus or Toyota dealers to find one that will do it. It varies a lot as to what they tell you. There may even be a software update.

I just read in the Sienna forum that there are firmware updates. Also you may be covered under the 6 year - 70,000 mile powertrain warranty, even if it is slightly over, the problems with the 8 speed are so well known, and there are so many technical service bulletins, they will probably take care of it for free. If not, complain to Lexus Corporate.

https://www.toyotanation.com/threads...fixed.1672696/

 

ATF refreshment is a good idea if it has never been done.

Also, how old is your battery? Weak and dying batteries can cause all sorts of faulty transmission behavior.

 

Thank you both for your responses.

Clutchless - I will look into your recommendations mentioned above. I will give the Techron Complete Fuel System Cleaner a shot first to see if that mitigates the issue and then next inline if that's not the solution.

It's good to hear Lexus may have some accountability if need be. I will search around for more TSB relevant to
the problem.

RX in NC - I purchased the vehicle in June. The Carfax says Lexus replaced the battery in April.

Here's the odd thing, the behavior of throttle response or shift points is very temperamental, like a crazy ex-girlfriend. It drives perfect one day and not so well another. Odd. Case in point, this morning on my commute to work, I noticed very little lag, and the vehicle was responsive. I gave it the beans from rolling multiple times, and I did not experience the dramatic lag I experienced in the previous days.